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linux/drivers/scsi/virtio_scsi.c

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/*
* Virtio SCSI HBA driver
*
* Copyright IBM Corp. 2010
* Copyright Red Hat, Inc. 2011
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Paolo Bonzini <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mempool.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/virtio_scsi.h>
#include <linux/cpu.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#define VIRTIO_SCSI_MEMPOOL_SZ 64
#define VIRTIO_SCSI_EVENT_LEN 8
#define VIRTIO_SCSI_VQ_BASE 2
/* Command queue element */
struct virtio_scsi_cmd {
struct scsi_cmnd *sc;
struct completion *comp;
union {
struct virtio_scsi_cmd_req cmd;
struct virtio_scsi_ctrl_tmf_req tmf;
struct virtio_scsi_ctrl_an_req an;
} req;
union {
struct virtio_scsi_cmd_resp cmd;
struct virtio_scsi_ctrl_tmf_resp tmf;
struct virtio_scsi_ctrl_an_resp an;
struct virtio_scsi_event evt;
} resp;
} ____cacheline_aligned_in_smp;
struct virtio_scsi_event_node {
struct virtio_scsi *vscsi;
struct virtio_scsi_event event;
struct work_struct work;
};
struct virtio_scsi_vq {
/* Protects vq */
spinlock_t vq_lock;
struct virtqueue *vq;
};
/*
* Per-target queue state.
*
* This struct holds the data needed by the queue steering policy. When a
* target is sent multiple requests, we need to drive them to the same queue so
* that FIFO processing order is kept. However, if a target was idle, we can
* choose a queue arbitrarily. In this case the queue is chosen according to
* the current VCPU, so the driver expects the number of request queues to be
* equal to the number of VCPUs. This makes it easy and fast to select the
* queue, and also lets the driver optimize the IRQ affinity for the virtqueues
* (each virtqueue's affinity is set to the CPU that "owns" the queue).
*
* An interesting effect of this policy is that only writes to req_vq need to
* take the tgt_lock. Read can be done outside the lock because:
*
* - writes of req_vq only occur when atomic_inc_return(&tgt->reqs) returns 1.
* In that case, no other CPU is reading req_vq: even if they were in
* virtscsi_queuecommand_multi, they would be spinning on tgt_lock.
*
* - reads of req_vq only occur when the target is not idle (reqs != 0).
* A CPU that enters virtscsi_queuecommand_multi will not modify req_vq.
*
* Similarly, decrements of reqs are never concurrent with writes of req_vq.
* Thus they can happen outside the tgt_lock, provided of course we make reqs
* an atomic_t.
*/
struct virtio_scsi_target_state {
/* This spinlock never held at the same time as vq_lock. */
spinlock_t tgt_lock;
/* Count of outstanding requests. */
atomic_t reqs;
/* Currently active virtqueue for requests sent to this target. */
struct virtio_scsi_vq *req_vq;
};
/* Driver instance state */
struct virtio_scsi {
struct virtio_device *vdev;
/* Get some buffers ready for event vq */
struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
u32 num_queues;
/* If the affinity hint is set for virtqueues */
bool affinity_hint_set;
/* CPU hotplug notifier */
struct notifier_block nb;
struct virtio_scsi_vq ctrl_vq;
struct virtio_scsi_vq event_vq;
struct virtio_scsi_vq req_vqs[];
};
static struct kmem_cache *virtscsi_cmd_cache;
static mempool_t *virtscsi_cmd_pool;
static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
{
return vdev->priv;
}
static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
{
if (!resid)
return;
if (!scsi_bidi_cmnd(sc)) {
scsi_set_resid(sc, resid);
return;
}
scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
}
/**
* virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
*
* Called with vq_lock held.
*/
static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
{
struct virtio_scsi_cmd *cmd = buf;
struct scsi_cmnd *sc = cmd->sc;
struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
struct virtio_scsi_target_state *tgt =
scsi_target(sc->device)->hostdata;
dev_dbg(&sc->device->sdev_gendev,
"cmd %p response %u status %#02x sense_len %u\n",
sc, resp->response, resp->status, resp->sense_len);
sc->result = resp->status;
virtscsi_compute_resid(sc, resp->resid);
switch (resp->response) {
case VIRTIO_SCSI_S_OK:
set_host_byte(sc, DID_OK);
break;
case VIRTIO_SCSI_S_OVERRUN:
set_host_byte(sc, DID_ERROR);
break;
case VIRTIO_SCSI_S_ABORTED:
set_host_byte(sc, DID_ABORT);
break;
case VIRTIO_SCSI_S_BAD_TARGET:
set_host_byte(sc, DID_BAD_TARGET);
break;
case VIRTIO_SCSI_S_RESET:
set_host_byte(sc, DID_RESET);
break;
case VIRTIO_SCSI_S_BUSY:
set_host_byte(sc, DID_BUS_BUSY);
break;
case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
break;
case VIRTIO_SCSI_S_TARGET_FAILURE:
set_host_byte(sc, DID_TARGET_FAILURE);
break;
case VIRTIO_SCSI_S_NEXUS_FAILURE:
set_host_byte(sc, DID_NEXUS_FAILURE);
break;
default:
scmd_printk(KERN_WARNING, sc, "Unknown response %d",
resp->response);
/* fall through */
case VIRTIO_SCSI_S_FAILURE:
set_host_byte(sc, DID_ERROR);
break;
}
WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
if (sc->sense_buffer) {
memcpy(sc->sense_buffer, resp->sense,
min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
if (resp->sense_len)
set_driver_byte(sc, DRIVER_SENSE);
}
mempool_free(cmd, virtscsi_cmd_pool);
sc->scsi_done(sc);
atomic_dec(&tgt->reqs);
}
static void virtscsi_vq_done(struct virtio_scsi *vscsi,
struct virtio_scsi_vq *virtscsi_vq,
void (*fn)(struct virtio_scsi *vscsi, void *buf))
{
void *buf;
unsigned int len;
unsigned long flags;
struct virtqueue *vq = virtscsi_vq->vq;
spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
do {
virtqueue_disable_cb(vq);
while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
fn(vscsi, buf);
if (unlikely(virtqueue_is_broken(vq)))
break;
} while (!virtqueue_enable_cb(vq));
spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
}
static void virtscsi_req_done(struct virtqueue *vq)
{
struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
int index = vq->index - VIRTIO_SCSI_VQ_BASE;
struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
/*
* Read req_vq before decrementing the reqs field in
* virtscsi_complete_cmd.
*
* With barriers:
*
* CPU #0 virtscsi_queuecommand_multi (CPU #1)
* ------------------------------------------------------------
* lock vq_lock
* read req_vq
* read reqs (reqs = 1)
* write reqs (reqs = 0)
* increment reqs (reqs = 1)
* write req_vq
*
* Possible reordering without barriers:
*
* CPU #0 virtscsi_queuecommand_multi (CPU #1)
* ------------------------------------------------------------
* lock vq_lock
* read reqs (reqs = 1)
* write reqs (reqs = 0)
* increment reqs (reqs = 1)
* write req_vq
* read (wrong) req_vq
*
* We do not need a full smp_rmb, because req_vq is required to get
* to tgt->reqs: tgt is &vscsi->tgt[sc->device->id], where sc is stored
* in the virtqueue as the user token.
*/
smp_read_barrier_depends();
virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
};
static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
{
struct virtio_scsi_cmd *cmd = buf;
if (cmd->comp)
complete_all(cmd->comp);
else
mempool_free(cmd, virtscsi_cmd_pool);
}
static void virtscsi_ctrl_done(struct virtqueue *vq)
{
struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
};
static int virtscsi_kick_event(struct virtio_scsi *vscsi,
struct virtio_scsi_event_node *event_node)
{
int err;
struct scatterlist sg;
unsigned long flags;
sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
GFP_ATOMIC);
if (!err)
virtqueue_kick(vscsi->event_vq.vq);
spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
return err;
}
static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
{
int i;
for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
vscsi->event_list[i].vscsi = vscsi;
virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
}
return 0;
}
static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
{
int i;
for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
cancel_work_sync(&vscsi->event_list[i].work);
}
static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
struct virtio_scsi_event *event)
{
struct scsi_device *sdev;
struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
unsigned int target = event->lun[1];
unsigned int lun = (event->lun[2] << 8) | event->lun[3];
switch (event->reason) {
case VIRTIO_SCSI_EVT_RESET_RESCAN:
scsi_add_device(shost, 0, target, lun);
break;
case VIRTIO_SCSI_EVT_RESET_REMOVED:
sdev = scsi_device_lookup(shost, 0, target, lun);
if (sdev) {
scsi_remove_device(sdev);
scsi_device_put(sdev);
} else {
pr_err("SCSI device %d 0 %d %d not found\n",
shost->host_no, target, lun);
}
break;
default:
pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
}
}
static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
struct virtio_scsi_event *event)
{
struct scsi_device *sdev;
struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
unsigned int target = event->lun[1];
unsigned int lun = (event->lun[2] << 8) | event->lun[3];
u8 asc = event->reason & 255;
u8 ascq = event->reason >> 8;
sdev = scsi_device_lookup(shost, 0, target, lun);
if (!sdev) {
pr_err("SCSI device %d 0 %d %d not found\n",
shost->host_no, target, lun);
return;
}
/* Handle "Parameters changed", "Mode parameters changed", and
"Capacity data has changed". */
if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
scsi_rescan_device(&sdev->sdev_gendev);
scsi_device_put(sdev);
}
static void virtscsi_handle_event(struct work_struct *work)
{
struct virtio_scsi_event_node *event_node =
container_of(work, struct virtio_scsi_event_node, work);
struct virtio_scsi *vscsi = event_node->vscsi;
struct virtio_scsi_event *event = &event_node->event;
if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
scsi_scan_host(virtio_scsi_host(vscsi->vdev));
}
switch (event->event) {
case VIRTIO_SCSI_T_NO_EVENT:
break;
case VIRTIO_SCSI_T_TRANSPORT_RESET:
virtscsi_handle_transport_reset(vscsi, event);
break;
case VIRTIO_SCSI_T_PARAM_CHANGE:
virtscsi_handle_param_change(vscsi, event);
break;
default:
pr_err("Unsupport virtio scsi event %x\n", event->event);
}
virtscsi_kick_event(vscsi, event_node);
}
static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
{
struct virtio_scsi_event_node *event_node = buf;
INIT_WORK(&event_node->work, virtscsi_handle_event);
schedule_work(&event_node->work);
}
static void virtscsi_event_done(struct virtqueue *vq)
{
struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
};
/**
* virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
* @vq : the struct virtqueue we're talking about
* @cmd : command structure
* @req_size : size of the request buffer
* @resp_size : size of the response buffer
* @gfp : flags to use for memory allocations
*/
static int virtscsi_add_cmd(struct virtqueue *vq,
struct virtio_scsi_cmd *cmd,
size_t req_size, size_t resp_size, gfp_t gfp)
{
struct scsi_cmnd *sc = cmd->sc;
struct scatterlist *sgs[4], req, resp;
struct sg_table *out, *in;
unsigned out_num = 0, in_num = 0;
out = in = NULL;
if (sc && sc->sc_data_direction != DMA_NONE) {
if (sc->sc_data_direction != DMA_FROM_DEVICE)
out = &scsi_out(sc)->table;
if (sc->sc_data_direction != DMA_TO_DEVICE)
in = &scsi_in(sc)->table;
}
/* Request header. */
sg_init_one(&req, &cmd->req, req_size);
sgs[out_num++] = &req;
/* Data-out buffer. */
if (out)
sgs[out_num++] = out->sgl;
/* Response header. */
sg_init_one(&resp, &cmd->resp, resp_size);
sgs[out_num + in_num++] = &resp;
/* Data-in buffer */
if (in)
sgs[out_num + in_num++] = in->sgl;
return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp);
}
static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
struct virtio_scsi_cmd *cmd,
size_t req_size, size_t resp_size, gfp_t gfp)
{
unsigned long flags;
int err;
bool needs_kick = false;
spin_lock_irqsave(&vq->vq_lock, flags);
err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size, gfp);
if (!err)
needs_kick = virtqueue_kick_prepare(vq->vq);
spin_unlock_irqrestore(&vq->vq_lock, flags);
if (needs_kick)
virtqueue_notify(vq->vq);
return err;
}
static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
struct virtio_scsi_vq *req_vq,
struct scsi_cmnd *sc)
{
struct virtio_scsi_cmd *cmd;
int ret;
struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
/* TODO: check feature bit and fail if unsupported? */
BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
dev_dbg(&sc->device->sdev_gendev,
"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
ret = SCSI_MLQUEUE_HOST_BUSY;
cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
if (!cmd)
goto out;
memset(cmd, 0, sizeof(*cmd));
cmd->sc = sc;
cmd->req.cmd = (struct virtio_scsi_cmd_req){
.lun[0] = 1,
.lun[1] = sc->device->id,
.lun[2] = (sc->device->lun >> 8) | 0x40,
.lun[3] = sc->device->lun & 0xff,
.tag = (unsigned long)sc,
.task_attr = VIRTIO_SCSI_S_SIMPLE,
.prio = 0,
.crn = 0,
};
BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
if (virtscsi_kick_cmd(req_vq, cmd,
sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
GFP_ATOMIC) == 0)
ret = 0;
else
mempool_free(cmd, virtscsi_cmd_pool);
out:
return ret;
}
static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
struct scsi_cmnd *sc)
{
struct virtio_scsi *vscsi = shost_priv(sh);
struct virtio_scsi_target_state *tgt =
scsi_target(sc->device)->hostdata;
atomic_inc(&tgt->reqs);
return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
}
static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
struct virtio_scsi_target_state *tgt)
{
struct virtio_scsi_vq *vq;
unsigned long flags;
u32 queue_num;
spin_lock_irqsave(&tgt->tgt_lock, flags);
/*
* The memory barrier after atomic_inc_return matches
* the smp_read_barrier_depends() in virtscsi_req_done.
*/
if (atomic_inc_return(&tgt->reqs) > 1)
vq = ACCESS_ONCE(tgt->req_vq);
else {
queue_num = smp_processor_id();
while (unlikely(queue_num >= vscsi->num_queues))
queue_num -= vscsi->num_queues;
tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
}
spin_unlock_irqrestore(&tgt->tgt_lock, flags);
return vq;
}
static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
struct scsi_cmnd *sc)
{
struct virtio_scsi *vscsi = shost_priv(sh);
struct virtio_scsi_target_state *tgt =
scsi_target(sc->device)->hostdata;
struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
return virtscsi_queuecommand(vscsi, req_vq, sc);
}
static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
{
DECLARE_COMPLETION_ONSTACK(comp);
int ret = FAILED;
cmd->comp = &comp;
if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
GFP_NOIO) < 0)
goto out;
wait_for_completion(&comp);
if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
ret = SUCCESS;
out:
mempool_free(cmd, virtscsi_cmd_pool);
return ret;
}
static int virtscsi_device_reset(struct scsi_cmnd *sc)
{
struct virtio_scsi *vscsi = shost_priv(sc->device->host);
struct virtio_scsi_cmd *cmd;
sdev_printk(KERN_INFO, sc->device, "device reset\n");
cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
if (!cmd)
return FAILED;
memset(cmd, 0, sizeof(*cmd));
cmd->sc = sc;
cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
.type = VIRTIO_SCSI_T_TMF,
.subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
.lun[0] = 1,
.lun[1] = sc->device->id,
.lun[2] = (sc->device->lun >> 8) | 0x40,
.lun[3] = sc->device->lun & 0xff,
};
return virtscsi_tmf(vscsi, cmd);
}
static int virtscsi_abort(struct scsi_cmnd *sc)
{
struct virtio_scsi *vscsi = shost_priv(sc->device->host);
struct virtio_scsi_cmd *cmd;
scmd_printk(KERN_INFO, sc, "abort\n");
cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
if (!cmd)
return FAILED;
memset(cmd, 0, sizeof(*cmd));
cmd->sc = sc;
cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
.type = VIRTIO_SCSI_T_TMF,
.subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
.lun[0] = 1,
.lun[1] = sc->device->id,
.lun[2] = (sc->device->lun >> 8) | 0x40,
.lun[3] = sc->device->lun & 0xff,
.tag = (unsigned long)sc,
};
return virtscsi_tmf(vscsi, cmd);
}
static int virtscsi_target_alloc(struct scsi_target *starget)
{
struct virtio_scsi_target_state *tgt =
kmalloc(sizeof(*tgt), GFP_KERNEL);
if (!tgt)
return -ENOMEM;
spin_lock_init(&tgt->tgt_lock);
atomic_set(&tgt->reqs, 0);
tgt->req_vq = NULL;
starget->hostdata = tgt;
return 0;
}
static void virtscsi_target_destroy(struct scsi_target *starget)
{
struct virtio_scsi_target_state *tgt = starget->hostdata;
kfree(tgt);
}
static struct scsi_host_template virtscsi_host_template_single = {
.module = THIS_MODULE,
.name = "Virtio SCSI HBA",
.proc_name = "virtio_scsi",
.this_id = -1,
.queuecommand = virtscsi_queuecommand_single,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,
.can_queue = 1024,
.dma_boundary = UINT_MAX,
.use_clustering = ENABLE_CLUSTERING,
.target_alloc = virtscsi_target_alloc,
.target_destroy = virtscsi_target_destroy,
};
static struct scsi_host_template virtscsi_host_template_multi = {
.module = THIS_MODULE,
.name = "Virtio SCSI HBA",
.proc_name = "virtio_scsi",
.this_id = -1,
.queuecommand = virtscsi_queuecommand_multi,
.eh_abort_handler = virtscsi_abort,
.eh_device_reset_handler = virtscsi_device_reset,
.can_queue = 1024,
.dma_boundary = UINT_MAX,
.use_clustering = ENABLE_CLUSTERING,
.target_alloc = virtscsi_target_alloc,
.target_destroy = virtscsi_target_destroy,
};
#define virtscsi_config_get(vdev, fld) \
({ \
typeof(((struct virtio_scsi_config *)0)->fld) __val; \
virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
__val; \
})
#define virtscsi_config_set(vdev, fld, val) \
do { \
typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
} while(0)
static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
{
int i;
int cpu;
/* In multiqueue mode, when the number of cpu is equal
* to the number of request queues, we let the qeueues
* to be private to one cpu by setting the affinity hint
* to eliminate the contention.
*/
if ((vscsi->num_queues == 1 ||
vscsi->num_queues != num_online_cpus()) && affinity) {
if (vscsi->affinity_hint_set)
affinity = false;
else
return;
}
if (affinity) {
i = 0;
for_each_online_cpu(cpu) {
virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
i++;
}
vscsi->affinity_hint_set = true;
} else {
for (i = 0; i < vscsi->num_queues; i++) {
if (!vscsi->req_vqs[i].vq)
continue;
virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
}
vscsi->affinity_hint_set = false;
}
}
static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
{
get_online_cpus();
__virtscsi_set_affinity(vscsi, affinity);
put_online_cpus();
}
static int virtscsi_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
switch(action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
__virtscsi_set_affinity(vscsi, true);
break;
default:
break;
}
return NOTIFY_OK;
}
static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
struct virtqueue *vq)
{
spin_lock_init(&virtscsi_vq->vq_lock);
virtscsi_vq->vq = vq;
}
static void virtscsi_scan(struct virtio_device *vdev)
{
struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
scsi_scan_host(shost);
}
static void virtscsi_remove_vqs(struct virtio_device *vdev)
{
struct Scsi_Host *sh = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
virtscsi_set_affinity(vscsi, false);
/* Stop all the virtqueues. */
vdev->config->reset(vdev);
vdev->config->del_vqs(vdev);
}
static int virtscsi_init(struct virtio_device *vdev,
struct virtio_scsi *vscsi)
{
int err;
u32 i;
u32 num_vqs;
vq_callback_t **callbacks;
const char **names;
struct virtqueue **vqs;
num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
if (!callbacks || !vqs || !names) {
err = -ENOMEM;
goto out;
}
callbacks[0] = virtscsi_ctrl_done;
callbacks[1] = virtscsi_event_done;
names[0] = "control";
names[1] = "event";
for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
callbacks[i] = virtscsi_req_done;
names[i] = "request";
}
/* Discover virtqueues and write information to configuration. */
err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
if (err)
goto out;
virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
vqs[i]);
virtscsi_set_affinity(vscsi, true);
virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
virtscsi_kick_event_all(vscsi);
err = 0;
out:
kfree(names);
kfree(callbacks);
kfree(vqs);
if (err)
virtscsi_remove_vqs(vdev);
return err;
}
static int virtscsi_probe(struct virtio_device *vdev)
{
struct Scsi_Host *shost;
struct virtio_scsi *vscsi;
int err;
u32 sg_elems, num_targets;
u32 cmd_per_lun;
u32 num_queues;
struct scsi_host_template *hostt;
/* We need to know how many queues before we allocate. */
num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
num_targets = virtscsi_config_get(vdev, max_target) + 1;
if (num_queues == 1)
hostt = &virtscsi_host_template_single;
else
hostt = &virtscsi_host_template_multi;
shost = scsi_host_alloc(hostt,
sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
if (!shost)
return -ENOMEM;
sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
shost->sg_tablesize = sg_elems;
vscsi = shost_priv(shost);
vscsi->vdev = vdev;
vscsi->num_queues = num_queues;
vdev->priv = shost;
err = virtscsi_init(vdev, vscsi);
if (err)
goto virtscsi_init_failed;
vscsi->nb.notifier_call = &virtscsi_cpu_callback;
err = register_hotcpu_notifier(&vscsi->nb);
if (err) {
pr_err("registering cpu notifier failed\n");
goto scsi_add_host_failed;
}
cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
/* LUNs > 256 are reported with format 1, so they go in the range
* 16640-32767.
*/
shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
shost->max_id = num_targets;
shost->max_channel = 0;
shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
err = scsi_add_host(shost, &vdev->dev);
if (err)
goto scsi_add_host_failed;
/*
* scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
* after VIRTIO_CONFIG_S_DRIVER_OK has been set..
*/
return 0;
scsi_add_host_failed:
vdev->config->del_vqs(vdev);
virtscsi_init_failed:
scsi_host_put(shost);
return err;
}
static void virtscsi_remove(struct virtio_device *vdev)
{
struct Scsi_Host *shost = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(shost);
if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
virtscsi_cancel_event_work(vscsi);
scsi_remove_host(shost);
unregister_hotcpu_notifier(&vscsi->nb);
virtscsi_remove_vqs(vdev);
scsi_host_put(shost);
}
#ifdef CONFIG_PM_SLEEP
static int virtscsi_freeze(struct virtio_device *vdev)
{
struct Scsi_Host *sh = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
unregister_hotcpu_notifier(&vscsi->nb);
virtscsi_remove_vqs(vdev);
return 0;
}
static int virtscsi_restore(struct virtio_device *vdev)
{
struct Scsi_Host *sh = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
int err;
err = virtscsi_init(vdev, vscsi);
if (err)
return err;
err = register_hotcpu_notifier(&vscsi->nb);
if (err)
vdev->config->del_vqs(vdev);
return err;
}
#endif
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
{ 0 },
};
static unsigned int features[] = {
VIRTIO_SCSI_F_HOTPLUG,
VIRTIO_SCSI_F_CHANGE,
};
static struct virtio_driver virtio_scsi_driver = {
.feature_table = features,
.feature_table_size = ARRAY_SIZE(features),
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
.probe = virtscsi_probe,
.scan = virtscsi_scan,
#ifdef CONFIG_PM_SLEEP
.freeze = virtscsi_freeze,
.restore = virtscsi_restore,
#endif
.remove = virtscsi_remove,
};
static int __init init(void)
{
int ret = -ENOMEM;
virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
if (!virtscsi_cmd_cache) {
pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
goto error;
}
virtscsi_cmd_pool =
mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
virtscsi_cmd_cache);
if (!virtscsi_cmd_pool) {
pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
goto error;
}
ret = register_virtio_driver(&virtio_scsi_driver);
if (ret < 0)
goto error;
return 0;
error:
if (virtscsi_cmd_pool) {
mempool_destroy(virtscsi_cmd_pool);
virtscsi_cmd_pool = NULL;
}
if (virtscsi_cmd_cache) {
kmem_cache_destroy(virtscsi_cmd_cache);
virtscsi_cmd_cache = NULL;
}
return ret;
}
static void __exit fini(void)
{
unregister_virtio_driver(&virtio_scsi_driver);
mempool_destroy(virtscsi_cmd_pool);
kmem_cache_destroy(virtscsi_cmd_cache);
}
module_init(init);
module_exit(fini);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio SCSI HBA driver");
MODULE_LICENSE("GPL");
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