linux/drivers/target/target_core_user.c

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target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
/*
* Copyright (C) 2013 Shaohua Li <shli@kernel.org>
* Copyright (C) 2014 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/timer.h>
#include <linux/parser.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <linux/uio_driver.h>
#include <net/genetlink.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_backend.h>
#include <target/target_core_backend_configfs.h>
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
#include <linux/target_core_user.h>
/*
* Define a shared-memory interface for LIO to pass SCSI commands and
* data to userspace for processing. This is to allow backends that
* are too complex for in-kernel support to be possible.
*
* It uses the UIO framework to do a lot of the device-creation and
* introspection work for us.
*
* See the .h file for how the ring is laid out. Note that while the
* command ring is defined, the particulars of the data area are
* not. Offset values in the command entry point to other locations
* internal to the mmap()ed area. There is separate space outside the
* command ring for data buffers. This leaves maximum flexibility for
* moving buffer allocations, or even page flipping or other
* allocation techniques, without altering the command ring layout.
*
* SECURITY:
* The user process must be assumed to be malicious. There's no way to
* prevent it breaking the command ring protocol if it wants, but in
* order to prevent other issues we must only ever read *data* from
* the shared memory area, not offsets or sizes. This applies to
* command ring entries as well as the mailbox. Extra code needed for
* this may have a 'UAM' comment.
*/
#define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
#define CMDR_SIZE (16 * 4096)
#define DATA_SIZE (257 * 4096)
#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
static struct device *tcmu_root_device;
struct tcmu_hba {
u32 host_id;
};
/* User wants all cmds or just some */
enum passthru_level {
TCMU_PASS_ALL = 0,
TCMU_PASS_IO,
TCMU_PASS_INVALID,
};
#define TCMU_CONFIG_LEN 256
struct tcmu_dev {
struct se_device se_dev;
char *name;
struct se_hba *hba;
#define TCMU_DEV_BIT_OPEN 0
#define TCMU_DEV_BIT_BROKEN 1
unsigned long flags;
enum passthru_level pass_level;
struct uio_info uio_info;
struct tcmu_mailbox *mb_addr;
size_t dev_size;
u32 cmdr_size;
u32 cmdr_last_cleaned;
/* Offset of data ring from start of mb */
size_t data_off;
size_t data_size;
/* Ring head + tail values. */
/* Must add data_off and mb_addr to get the address */
size_t data_head;
size_t data_tail;
wait_queue_head_t wait_cmdr;
/* TODO should this be a mutex? */
spinlock_t cmdr_lock;
struct idr commands;
spinlock_t commands_lock;
struct timer_list timeout;
char dev_config[TCMU_CONFIG_LEN];
};
#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
#define CMDR_OFF sizeof(struct tcmu_mailbox)
struct tcmu_cmd {
struct se_cmd *se_cmd;
struct tcmu_dev *tcmu_dev;
uint16_t cmd_id;
/* Can't use se_cmd->data_length when cleaning up expired cmds, because if
cmd has been completed then accessing se_cmd is off limits */
size_t data_length;
unsigned long deadline;
#define TCMU_CMD_BIT_EXPIRED 0
unsigned long flags;
};
static struct kmem_cache *tcmu_cmd_cache;
/* multicast group */
enum tcmu_multicast_groups {
TCMU_MCGRP_CONFIG,
};
static const struct genl_multicast_group tcmu_mcgrps[] = {
[TCMU_MCGRP_CONFIG] = { .name = "config", },
};
/* Our generic netlink family */
static struct genl_family tcmu_genl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = "TCM-USER",
.version = 1,
.maxattr = TCMU_ATTR_MAX,
.mcgrps = tcmu_mcgrps,
.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
};
static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
{
struct se_device *se_dev = se_cmd->se_dev;
struct tcmu_dev *udev = TCMU_DEV(se_dev);
struct tcmu_cmd *tcmu_cmd;
int cmd_id;
tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
if (!tcmu_cmd)
return NULL;
tcmu_cmd->se_cmd = se_cmd;
tcmu_cmd->tcmu_dev = udev;
tcmu_cmd->data_length = se_cmd->data_length;
tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
idr_preload(GFP_KERNEL);
spin_lock_irq(&udev->commands_lock);
cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
USHRT_MAX, GFP_NOWAIT);
spin_unlock_irq(&udev->commands_lock);
idr_preload_end();
if (cmd_id < 0) {
kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
return NULL;
}
tcmu_cmd->cmd_id = cmd_id;
return tcmu_cmd;
}
static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
{
unsigned long offset = (unsigned long) vaddr & ~PAGE_MASK;
size = round_up(size+offset, PAGE_SIZE);
vaddr -= offset;
while (size) {
flush_dcache_page(virt_to_page(vaddr));
size -= PAGE_SIZE;
}
}
/*
* Some ring helper functions. We don't assume size is a power of 2 so
* we can't use circ_buf.h.
*/
static inline size_t spc_used(size_t head, size_t tail, size_t size)
{
int diff = head - tail;
if (diff >= 0)
return diff;
else
return size + diff;
}
static inline size_t spc_free(size_t head, size_t tail, size_t size)
{
/* Keep 1 byte unused or we can't tell full from empty */
return (size - spc_used(head, tail, size) - 1);
}
static inline size_t head_to_end(size_t head, size_t size)
{
return size - head;
}
#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
/*
* We can't queue a command until we have space available on the cmd ring *and* space
* space avail on the data ring.
*
* Called with ring lock held.
*/
static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
{
struct tcmu_mailbox *mb = udev->mb_addr;
size_t space;
u32 cmd_head;
size_t cmd_needed;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
tcmu_flush_dcache_range(mb, sizeof(*mb));
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
/*
* If cmd end-of-ring space is too small then we need space for a NOP plus
* original cmd - cmds are internally contiguous.
*/
if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
cmd_needed = cmd_size;
else
cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
if (space < cmd_needed) {
pr_debug("no cmd space: %u %u %u\n", cmd_head,
udev->cmdr_last_cleaned, udev->cmdr_size);
return false;
}
space = spc_free(udev->data_head, udev->data_tail, udev->data_size);
if (space < data_needed) {
pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
udev->data_tail, udev->data_size);
return false;
}
return true;
}
static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
size_t base_command_size, command_size;
struct tcmu_mailbox *mb;
struct tcmu_cmd_entry *entry;
int i;
struct scatterlist *sg;
struct iovec *iov;
int iov_cnt = 0;
uint32_t cmd_head;
uint64_t cdb_off;
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
return -EINVAL;
/*
* Must be a certain minimum size for response sense info, but
* also may be larger if the iov array is large.
*
* iovs = sgl_nents+1, for end-of-ring case, plus another 1
* b/c size == offsetof one-past-element.
*/
base_command_size = max(offsetof(struct tcmu_cmd_entry,
req.iov[se_cmd->t_data_nents + 2]),
sizeof(struct tcmu_cmd_entry));
command_size = base_command_size
+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
spin_lock_irq(&udev->cmdr_lock);
mb = udev->mb_addr;
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
if ((command_size > (udev->cmdr_size / 2))
|| tcmu_cmd->data_length > (udev->data_size - 1))
pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
"cmd/data ring buffers\n", command_size, tcmu_cmd->data_length,
udev->cmdr_size, udev->data_size);
while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) {
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
int ret;
DEFINE_WAIT(__wait);
prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
pr_debug("sleeping for ring space\n");
spin_unlock_irq(&udev->cmdr_lock);
ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
finish_wait(&udev->wait_cmdr, &__wait);
if (!ret) {
pr_warn("tcmu: command timed out\n");
return -ETIMEDOUT;
}
spin_lock_irq(&udev->cmdr_lock);
/* We dropped cmdr_lock, cmd_head is stale */
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
}
/* Insert a PAD if end-of-ring space is too small */
if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
entry = (void *) mb + CMDR_OFF + cmd_head;
tcmu_flush_dcache_range(entry, sizeof(*entry));
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
entry->hdr.cmd_id = 0; /* not used for PAD */
entry->hdr.kflags = 0;
entry->hdr.uflags = 0;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
WARN_ON(cmd_head != 0);
}
entry = (void *) mb + CMDR_OFF + cmd_head;
tcmu_flush_dcache_range(entry, sizeof(*entry));
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
entry->hdr.cmd_id = tcmu_cmd->cmd_id;
entry->hdr.kflags = 0;
entry->hdr.uflags = 0;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
/*
* Fix up iovecs, and handle if allocation in data ring wrapped.
*/
iov = &entry->req.iov[0];
for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
size_t copy_bytes = min((size_t)sg->length,
head_to_end(udev->data_head, udev->data_size));
void *from = kmap_atomic(sg_page(sg)) + sg->offset;
void *to = (void *) mb + udev->data_off + udev->data_head;
if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) {
memcpy(to, from, copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
/* Even iov_base is relative to mb_addr */
iov->iov_len = copy_bytes;
iov->iov_base = (void __user *) udev->data_off +
udev->data_head;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
iov_cnt++;
iov++;
UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
/* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
if (sg->length != copy_bytes) {
from += copy_bytes;
copy_bytes = sg->length - copy_bytes;
iov->iov_len = copy_bytes;
iov->iov_base = (void __user *) udev->data_off +
udev->data_head;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
if (se_cmd->data_direction == DMA_TO_DEVICE) {
to = (void *) mb + udev->data_off + udev->data_head;
memcpy(to, from, copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
iov_cnt++;
iov++;
UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
}
kunmap_atomic(from);
}
entry->req.iov_cnt = iov_cnt;
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
entry->req.iov_bidi_cnt = 0;
entry->req.iov_dif_cnt = 0;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
/* All offsets relative to mb_addr, not start of entry! */
cdb_off = CMDR_OFF + cmd_head + base_command_size;
memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
entry->req.cdb_off = cdb_off;
tcmu_flush_dcache_range(entry, sizeof(*entry));
UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
tcmu_flush_dcache_range(mb, sizeof(*mb));
spin_unlock_irq(&udev->cmdr_lock);
/* TODO: only if FLUSH and FUA? */
uio_event_notify(&udev->uio_info);
mod_timer(&udev->timeout,
round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
return 0;
}
static int tcmu_queue_cmd(struct se_cmd *se_cmd)
{
struct se_device *se_dev = se_cmd->se_dev;
struct tcmu_dev *udev = TCMU_DEV(se_dev);
struct tcmu_cmd *tcmu_cmd;
int ret;
tcmu_cmd = tcmu_alloc_cmd(se_cmd);
if (!tcmu_cmd)
return -ENOMEM;
ret = tcmu_queue_cmd_ring(tcmu_cmd);
if (ret < 0) {
pr_err("TCMU: Could not queue command\n");
spin_lock_irq(&udev->commands_lock);
idr_remove(&udev->commands, tcmu_cmd->cmd_id);
spin_unlock_irq(&udev->commands_lock);
kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
}
return ret;
}
static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
{
struct se_cmd *se_cmd = cmd->se_cmd;
struct tcmu_dev *udev = cmd->tcmu_dev;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
/* cmd has been completed already from timeout, just reclaim data
ring space */
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
return;
}
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
cmd->se_cmd);
transport_generic_request_failure(cmd->se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
return;
}
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
se_cmd->scsi_sense_length);
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
}
else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
struct scatterlist *sg;
int i;
/* It'd be easier to look at entry's iovec again, but UAM */
for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
size_t copy_bytes;
void *to;
void *from;
copy_bytes = min((size_t)sg->length,
head_to_end(udev->data_tail, udev->data_size));
to = kmap_atomic(sg_page(sg)) + sg->offset;
WARN_ON(sg->length + sg->offset > PAGE_SIZE);
from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to, from, copy_bytes);
UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
/* Uh oh, wrapped the data buffer for this sg's data */
if (sg->length != copy_bytes) {
from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
WARN_ON(udev->data_tail);
to += copy_bytes;
copy_bytes = sg->length - copy_bytes;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to, from, copy_bytes);
UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
}
kunmap_atomic(to);
}
} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
} else {
pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction);
}
target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
}
static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
{
struct tcmu_mailbox *mb;
LIST_HEAD(cpl_cmds);
unsigned long flags;
int handled = 0;
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
pr_err("ring broken, not handling completions\n");
return 0;
}
spin_lock_irqsave(&udev->cmdr_lock, flags);
mb = udev->mb_addr;
tcmu_flush_dcache_range(mb, sizeof(*mb));
while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
struct tcmu_cmd *cmd;
tcmu_flush_dcache_range(entry, sizeof(*entry));
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
UPDATE_HEAD(udev->cmdr_last_cleaned,
tcmu_hdr_get_len(entry->hdr.len_op),
udev->cmdr_size);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
continue;
}
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
spin_lock(&udev->commands_lock);
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
cmd = idr_find(&udev->commands, entry->hdr.cmd_id);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
if (cmd)
idr_remove(&udev->commands, cmd->cmd_id);
spin_unlock(&udev->commands_lock);
if (!cmd) {
pr_err("cmd_id not found, ring is broken\n");
set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
break;
}
tcmu_handle_completion(cmd, entry);
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
UPDATE_HEAD(udev->cmdr_last_cleaned,
tcmu_hdr_get_len(entry->hdr.len_op),
udev->cmdr_size);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
handled++;
}
if (mb->cmd_tail == mb->cmd_head)
del_timer(&udev->timeout); /* no more pending cmds */
spin_unlock_irqrestore(&udev->cmdr_lock, flags);
wake_up(&udev->wait_cmdr);
return handled;
}
static int tcmu_check_expired_cmd(int id, void *p, void *data)
{
struct tcmu_cmd *cmd = p;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
return 0;
if (!time_after(cmd->deadline, jiffies))
return 0;
set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
return 0;
}
static void tcmu_device_timedout(unsigned long data)
{
struct tcmu_dev *udev = (struct tcmu_dev *)data;
unsigned long flags;
int handled;
handled = tcmu_handle_completions(udev);
pr_warn("%d completions handled from timeout\n", handled);
spin_lock_irqsave(&udev->commands_lock, flags);
idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
spin_unlock_irqrestore(&udev->commands_lock, flags);
/*
* We don't need to wakeup threads on wait_cmdr since they have their
* own timeout.
*/
}
static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
{
struct tcmu_hba *tcmu_hba;
tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
if (!tcmu_hba)
return -ENOMEM;
tcmu_hba->host_id = host_id;
hba->hba_ptr = tcmu_hba;
return 0;
}
static void tcmu_detach_hba(struct se_hba *hba)
{
kfree(hba->hba_ptr);
hba->hba_ptr = NULL;
}
static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
{
struct tcmu_dev *udev;
udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
if (!udev)
return NULL;
udev->name = kstrdup(name, GFP_KERNEL);
if (!udev->name) {
kfree(udev);
return NULL;
}
udev->hba = hba;
init_waitqueue_head(&udev->wait_cmdr);
spin_lock_init(&udev->cmdr_lock);
idr_init(&udev->commands);
spin_lock_init(&udev->commands_lock);
setup_timer(&udev->timeout, tcmu_device_timedout,
(unsigned long)udev);
udev->pass_level = TCMU_PASS_ALL;
return &udev->se_dev;
}
static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
{
struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
tcmu_handle_completions(tcmu_dev);
return 0;
}
/*
* mmap code from uio.c. Copied here because we want to hook mmap()
* and this stuff must come along.
*/
static int tcmu_find_mem_index(struct vm_area_struct *vma)
{
struct tcmu_dev *udev = vma->vm_private_data;
struct uio_info *info = &udev->uio_info;
if (vma->vm_pgoff < MAX_UIO_MAPS) {
if (info->mem[vma->vm_pgoff].size == 0)
return -1;
return (int)vma->vm_pgoff;
}
return -1;
}
static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct tcmu_dev *udev = vma->vm_private_data;
struct uio_info *info = &udev->uio_info;
struct page *page;
unsigned long offset;
void *addr;
int mi = tcmu_find_mem_index(vma);
if (mi < 0)
return VM_FAULT_SIGBUS;
/*
* We need to subtract mi because userspace uses offset = N*PAGE_SIZE
* to use mem[N].
*/
offset = (vmf->pgoff - mi) << PAGE_SHIFT;
addr = (void *)(unsigned long)info->mem[mi].addr + offset;
if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
page = virt_to_page(addr);
else
page = vmalloc_to_page(addr);
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct tcmu_vm_ops = {
.fault = tcmu_vma_fault,
};
static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &tcmu_vm_ops;
vma->vm_private_data = udev;
/* Ensure the mmap is exactly the right size */
if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
return -EINVAL;
return 0;
}
static int tcmu_open(struct uio_info *info, struct inode *inode)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
/* O_EXCL not supported for char devs, so fake it? */
if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
return -EBUSY;
pr_debug("open\n");
return 0;
}
static int tcmu_release(struct uio_info *info, struct inode *inode)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
pr_debug("close\n");
return 0;
}
static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
{
struct sk_buff *skb;
void *msg_header;
int ret = -ENOMEM;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
if (!skb)
return ret;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
if (!msg_header)
goto free_skb;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
if (ret < 0)
goto free_skb;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
if (ret < 0)
goto free_skb;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
netlink: make nlmsg_end() and genlmsg_end() void Contrary to common expectations for an "int" return, these functions return only a positive value -- if used correctly they cannot even return 0 because the message header will necessarily be in the skb. This makes the very common pattern of if (genlmsg_end(...) < 0) { ... } be a whole bunch of dead code. Many places also simply do return nlmsg_end(...); and the caller is expected to deal with it. This also commonly (at least for me) causes errors, because it is very common to write if (my_function(...)) /* error condition */ and if my_function() does "return nlmsg_end()" this is of course wrong. Additionally, there's not a single place in the kernel that actually needs the message length returned, and if anyone needs it later then it'll be very easy to just use skb->len there. Remove this, and make the functions void. This removes a bunch of dead code as described above. The patch adds lines because I did - return nlmsg_end(...); + nlmsg_end(...); + return 0; I could have preserved all the function's return values by returning skb->len, but instead I've audited all the places calling the affected functions and found that none cared. A few places actually compared the return value with <= 0 in dump functionality, but that could just be changed to < 0 with no change in behaviour, so I opted for the more efficient version. One instance of the error I've made numerous times now is also present in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't check for <0 or <=0 and thus broke out of the loop every single time. I've preserved this since it will (I think) have caused the messages to userspace to be formatted differently with just a single message for every SKB returned to userspace. It's possible that this isn't needed for the tools that actually use this, but I don't even know what they are so couldn't test that changing this behaviour would be acceptable. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-17 05:09:00 +08:00
genlmsg_end(skb, msg_header);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
ret = genlmsg_multicast(&tcmu_genl_family, skb, 0,
TCMU_MCGRP_CONFIG, GFP_KERNEL);
/* We don't care if no one is listening */
if (ret == -ESRCH)
ret = 0;
return ret;
free_skb:
nlmsg_free(skb);
return ret;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
}
static int tcmu_configure_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
struct tcmu_hba *hba = udev->hba->hba_ptr;
struct uio_info *info;
struct tcmu_mailbox *mb;
size_t size;
size_t used;
int ret = 0;
char *str;
info = &udev->uio_info;
size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
udev->dev_config);
size += 1; /* for \0 */
str = kmalloc(size, GFP_KERNEL);
if (!str)
return -ENOMEM;
used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
if (udev->dev_config[0])
snprintf(str + used, size - used, "/%s", udev->dev_config);
info->name = str;
udev->mb_addr = vzalloc(TCMU_RING_SIZE);
if (!udev->mb_addr) {
ret = -ENOMEM;
goto err_vzalloc;
}
/* mailbox fits in first part of CMDR space */
udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
udev->data_off = CMDR_SIZE;
udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
mb = udev->mb_addr;
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
mb->version = TCMU_MAILBOX_VERSION;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
mb->cmdr_off = CMDR_OFF;
mb->cmdr_size = udev->cmdr_size;
WARN_ON(!PAGE_ALIGNED(udev->data_off));
WARN_ON(udev->data_size % PAGE_SIZE);
target: Version 2 of TCMU ABI The initial version of TCMU (in 3.18) does not properly handle bidirectional SCSI commands -- those with both an in and out buffer. In looking to fix this it also became clear that TCMU's support for adding new types of entries (opcodes) to the command ring was broken. We need to fix this now, so that future issues can be handled properly by adding new opcodes. We make the most of this ABI break by enabling bidi cmd handling within TCMP_OP_CMD opcode. Add an iov_bidi_cnt field to tcmu_cmd_entry.req. This enables TCMU to describe bidi commands, but further kernel work is needed for full bidi support. Enlarge tcmu_cmd_entry_hdr by 32 bits by pulling in cmd_id and __pad1. Turn __pad1 into two 8 bit flags fields, for kernel-set and userspace-set flags, "kflags" and "uflags" respectively. Update version fields so userspace can tell the interface is changed. Update tcmu-design.txt with details of how new stuff works: - Specify an additional requirement for userspace to set UNKNOWN_OP (bit 0) in hdr.uflags for unknown/unhandled opcodes. - Define how Data-In and Data-Out fields are described in req.iov[] Changed in v2: - Change name of SKIPPED bit to UNKNOWN bit - PAD op does not set the bit any more - Change len_op helper functions to take just len_op, not the whole struct - Change version to 2 in missed spots, and use defines - Add 16 unused bytes to cmd_entry.req, in case additional SAM cmd parameters need to be included - Add iov_dif_cnt field to specify buffers used for DIF info in iov[] - Rearrange fields to naturally align cdb_off - Handle if userspace sets UNKNOWN_OP by indicating failure of the cmd - Wrap some overly long UPDATE_HEAD lines (Add missing req.iov_bidi_cnt + req.iov_dif_cnt zeroing - Ilias) Signed-off-by: Andy Grover <agrover@redhat.com> Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-04-15 08:30:04 +08:00
info->version = xstr(TCMU_MAILBOX_VERSION);
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
info->mem[0].name = "tcm-user command & data buffer";
info->mem[0].addr = (phys_addr_t) udev->mb_addr;
info->mem[0].size = TCMU_RING_SIZE;
info->mem[0].memtype = UIO_MEM_VIRTUAL;
info->irqcontrol = tcmu_irqcontrol;
info->irq = UIO_IRQ_CUSTOM;
info->mmap = tcmu_mmap;
info->open = tcmu_open;
info->release = tcmu_release;
ret = uio_register_device(tcmu_root_device, info);
if (ret)
goto err_register;
/* Other attributes can be configured in userspace */
dev->dev_attrib.hw_block_size = 512;
dev->dev_attrib.hw_max_sectors = 128;
dev->dev_attrib.hw_queue_depth = 128;
ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor);
if (ret)
goto err_netlink;
return 0;
err_netlink:
uio_unregister_device(&udev->uio_info);
err_register:
vfree(udev->mb_addr);
err_vzalloc:
kfree(info->name);
return ret;
}
static int tcmu_check_pending_cmd(int id, void *p, void *data)
{
struct tcmu_cmd *cmd = p;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
return 0;
return -EINVAL;
}
static void tcmu_free_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
int i;
del_timer_sync(&udev->timeout);
vfree(udev->mb_addr);
/* Upper layer should drain all requests before calling this */
spin_lock_irq(&udev->commands_lock);
i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL);
idr_destroy(&udev->commands);
spin_unlock_irq(&udev->commands_lock);
WARN_ON(i);
/* Device was configured */
if (udev->uio_info.uio_dev) {
tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor);
uio_unregister_device(&udev->uio_info);
kfree(udev->uio_info.name);
kfree(udev->name);
}
kfree(udev);
}
enum {
Opt_dev_config, Opt_dev_size, Opt_err, Opt_pass_level,
};
static match_table_t tokens = {
{Opt_dev_config, "dev_config=%s"},
{Opt_dev_size, "dev_size=%u"},
{Opt_pass_level, "pass_level=%u"},
{Opt_err, NULL}
};
static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
const char *page, ssize_t count)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
char *orig, *ptr, *opts, *arg_p;
substring_t args[MAX_OPT_ARGS];
int ret = 0, token;
int arg;
opts = kstrdup(page, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((ptr = strsep(&opts, ",\n")) != NULL) {
if (!*ptr)
continue;
token = match_token(ptr, tokens, args);
switch (token) {
case Opt_dev_config:
if (match_strlcpy(udev->dev_config, &args[0],
TCMU_CONFIG_LEN) == 0) {
ret = -EINVAL;
break;
}
pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
break;
case Opt_dev_size:
arg_p = match_strdup(&args[0]);
if (!arg_p) {
ret = -ENOMEM;
break;
}
ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
kfree(arg_p);
if (ret < 0)
pr_err("kstrtoul() failed for dev_size=\n");
break;
case Opt_pass_level:
match_int(args, &arg);
if (arg >= TCMU_PASS_INVALID) {
pr_warn("TCMU: Invalid pass_level: %d\n", arg);
break;
}
pr_debug("TCMU: Setting pass_level to %d\n", arg);
udev->pass_level = arg;
break;
default:
break;
}
}
kfree(orig);
return (!ret) ? count : ret;
}
static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
ssize_t bl = 0;
bl = sprintf(b + bl, "Config: %s ",
udev->dev_config[0] ? udev->dev_config : "NULL");
bl += sprintf(b + bl, "Size: %zu PassLevel: %u\n",
udev->dev_size, udev->pass_level);
return bl;
}
static sector_t tcmu_get_blocks(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
return div_u64(udev->dev_size - dev->dev_attrib.block_size,
dev->dev_attrib.block_size);
}
static sense_reason_t
tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents,
enum dma_data_direction data_direction)
{
int ret;
ret = tcmu_queue_cmd(se_cmd);
if (ret != 0)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
else
return TCM_NO_SENSE;
}
static sense_reason_t
tcmu_pass_op(struct se_cmd *se_cmd)
{
int ret = tcmu_queue_cmd(se_cmd);
if (ret != 0)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
else
return TCM_NO_SENSE;
}
static struct sbc_ops tcmu_sbc_ops = {
.execute_rw = tcmu_execute_rw,
.execute_sync_cache = tcmu_pass_op,
.execute_write_same = tcmu_pass_op,
.execute_write_same_unmap = tcmu_pass_op,
.execute_unmap = tcmu_pass_op,
};
static sense_reason_t
tcmu_parse_cdb(struct se_cmd *cmd)
{
unsigned char *cdb = cmd->t_task_cdb;
struct tcmu_dev *udev = TCMU_DEV(cmd->se_dev);
sense_reason_t ret;
switch (udev->pass_level) {
case TCMU_PASS_ALL:
/* We're just like pscsi, then */
/*
* For REPORT LUNS we always need to emulate the response, for everything
* else, pass it up.
*/
switch (cdb[0]) {
case REPORT_LUNS:
cmd->execute_cmd = spc_emulate_report_luns;
break;
case READ_6:
case READ_10:
case READ_12:
case READ_16:
case WRITE_6:
case WRITE_10:
case WRITE_12:
case WRITE_16:
case WRITE_VERIFY:
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
/* FALLTHROUGH */
default:
cmd->execute_cmd = tcmu_pass_op;
}
ret = TCM_NO_SENSE;
break;
case TCMU_PASS_IO:
ret = sbc_parse_cdb(cmd, &tcmu_sbc_ops);
break;
default:
pr_err("Unknown tcm-user pass level %d\n", udev->pass_level);
ret = TCM_CHECK_CONDITION_ABORT_CMD;
}
return ret;
}
DEF_TB_DEFAULT_ATTRIBS(tcmu);
static struct configfs_attribute *tcmu_backend_dev_attrs[] = {
&tcmu_dev_attrib_emulate_model_alias.attr,
&tcmu_dev_attrib_emulate_dpo.attr,
&tcmu_dev_attrib_emulate_fua_write.attr,
&tcmu_dev_attrib_emulate_fua_read.attr,
&tcmu_dev_attrib_emulate_write_cache.attr,
&tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr,
&tcmu_dev_attrib_emulate_tas.attr,
&tcmu_dev_attrib_emulate_tpu.attr,
&tcmu_dev_attrib_emulate_tpws.attr,
&tcmu_dev_attrib_emulate_caw.attr,
&tcmu_dev_attrib_emulate_3pc.attr,
&tcmu_dev_attrib_pi_prot_type.attr,
&tcmu_dev_attrib_hw_pi_prot_type.attr,
&tcmu_dev_attrib_pi_prot_format.attr,
&tcmu_dev_attrib_enforce_pr_isids.attr,
&tcmu_dev_attrib_is_nonrot.attr,
&tcmu_dev_attrib_emulate_rest_reord.attr,
&tcmu_dev_attrib_force_pr_aptpl.attr,
&tcmu_dev_attrib_hw_block_size.attr,
&tcmu_dev_attrib_block_size.attr,
&tcmu_dev_attrib_hw_max_sectors.attr,
&tcmu_dev_attrib_optimal_sectors.attr,
&tcmu_dev_attrib_hw_queue_depth.attr,
&tcmu_dev_attrib_queue_depth.attr,
&tcmu_dev_attrib_max_unmap_lba_count.attr,
&tcmu_dev_attrib_max_unmap_block_desc_count.attr,
&tcmu_dev_attrib_unmap_granularity.attr,
&tcmu_dev_attrib_unmap_granularity_alignment.attr,
&tcmu_dev_attrib_max_write_same_len.attr,
NULL,
};
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
static struct se_subsystem_api tcmu_template = {
.name = "user",
.inquiry_prod = "USER",
.inquiry_rev = TCMU_VERSION,
.owner = THIS_MODULE,
.transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
.attach_hba = tcmu_attach_hba,
.detach_hba = tcmu_detach_hba,
.alloc_device = tcmu_alloc_device,
.configure_device = tcmu_configure_device,
.free_device = tcmu_free_device,
.parse_cdb = tcmu_parse_cdb,
.set_configfs_dev_params = tcmu_set_configfs_dev_params,
.show_configfs_dev_params = tcmu_show_configfs_dev_params,
.get_device_type = sbc_get_device_type,
.get_blocks = tcmu_get_blocks,
};
static int __init tcmu_module_init(void)
{
struct target_backend_cits *tbc = &tcmu_template.tb_cits;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
int ret;
BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
sizeof(struct tcmu_cmd),
__alignof__(struct tcmu_cmd),
0, NULL);
if (!tcmu_cmd_cache)
return -ENOMEM;
tcmu_root_device = root_device_register("tcm_user");
if (IS_ERR(tcmu_root_device)) {
ret = PTR_ERR(tcmu_root_device);
goto out_free_cache;
}
ret = genl_register_family(&tcmu_genl_family);
if (ret < 0) {
goto out_unreg_device;
}
target_core_setup_sub_cits(&tcmu_template);
tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs;
target: Add a user-passthrough backstore Add a LIO storage engine that presents commands to userspace for execution. This would allow more complex backstores to be implemented out-of-kernel, and also make experimentation a-la FUSE (but at the SCSI level -- "SUSE"?) possible. It uses a mmap()able UIO device per LUN to share a command ring and data area. The commands are raw SCSI CDBs and iovs for in/out data. The command ring is also reused for returning scsi command status and optional sense data. This implementation is based on Shaohua Li's earlier version but heavily modified. Differences include: * Shared memory allocated by kernel, not locked-down user pages * Single ring for command request and response * Offsets instead of embedded pointers * Generic SCSI CDB passthrough instead of per-cmd specialization in ring format. * Uses UIO device instead of anon_file passed in mailbox. * Optional in-kernel handling of some commands. The main reason for these differences is to permit greater resiliency if the user process dies or hangs. Things not yet implemented (on purpose): * Zero copy. The data area is flexible enough to allow page flipping or backend-allocated pages to be used by fabrics, but it's not clear these are performance wins. Can come later. * Out-of-order command completion by userspace. Possible to add by just allowing userspace to change cmd_id in rsp cmd entries, but currently not supported. * No locks between kernel cmd submission and completion routines. Sounds like it's possible, but this can come later. * Sparse allocation of mmaped area. Current code vmallocs the whole thing. If the mapped area was larger and not fully mapped then the driver would have more freedom to change cmd and data area sizes based on demand. Current code open issues: * The use of idrs may be overkill -- we maybe can replace them with a simple counter to generate cmd_ids, and a hash table to get a cmd_id's associated pointer. * Use of a free-running counter for cmd ring instead of explicit modulo math. This would require power-of-2 cmd ring size. (Add kconfig depends NET - Randy) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2014-10-02 07:07:05 +08:00
ret = transport_subsystem_register(&tcmu_template);
if (ret)
goto out_unreg_genl;
return 0;
out_unreg_genl:
genl_unregister_family(&tcmu_genl_family);
out_unreg_device:
root_device_unregister(tcmu_root_device);
out_free_cache:
kmem_cache_destroy(tcmu_cmd_cache);
return ret;
}
static void __exit tcmu_module_exit(void)
{
transport_subsystem_release(&tcmu_template);
genl_unregister_family(&tcmu_genl_family);
root_device_unregister(tcmu_root_device);
kmem_cache_destroy(tcmu_cmd_cache);
}
MODULE_DESCRIPTION("TCM USER subsystem plugin");
MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
MODULE_LICENSE("GPL");
module_init(tcmu_module_init);
module_exit(tcmu_module_exit);