linux_old1/drivers/s390/scsi/zfcp_aux.c

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/*
* zfcp device driver
*
* Module interface and handling of zfcp data structures.
*
[SCSI] zfcp: status read buffers on first adapter open with link down Commit 64deb6efdc5504ce97b5c1c6f281fffbc150bd93 "[SCSI] zfcp: Use status_read_buf_num provided by FCP channel" started using a value returned by the channel but only evaluated the value if the fabric link is up. Commit 8d88cf3f3b9af4713642caeb221b6d6a42019001 "[SCSI] zfcp: Update status read mempool" introduced mempool resizings based on the above value. On setting an FCP device online for the very first time since boot, a new zeroed adapter object is allocated. If the link is down, the number of status read requests remains zero. Since just the config data exchange is incomplete, we proceed with adapter open recovery. However, we unconditionally call mempool_resize with adapter->stat_read_buf_num == 0 in this case. This causes a kernel message "kernel BUG at mm/mempool.c:131!" in process "zfcperp<FCP-device-bus-ID>" with last function mempool_resize in Krnl PSW and zfcp_erp_thread in the Call Trace. Don't evaluate channel values which are invalid on link down. The number of status read requests is always valid, evaluated, and set to a positive minimum greater than zero. The adapter open recovery can proceed and the channel has status read buffers to inform us on a future link up event. While we are not aware of any other code path that could result in mempool resize attempts of size zero, we still also initialize the number of status read buffers to be posted to a static minimum number on adapter object allocation. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> #2.6.35+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-04-26 23:34:54 +08:00
* Copyright IBM Corp. 2002, 2013
*/
/*
* Driver authors:
* Martin Peschke (originator of the driver)
* Raimund Schroeder
* Aron Zeh
* Wolfgang Taphorn
* Stefan Bader
* Heiko Carstens (kernel 2.6 port of the driver)
* Andreas Herrmann
* Maxim Shchetynin
* Volker Sameske
* Ralph Wuerthner
* Michael Loehr
* Swen Schillig
* Christof Schmitt
* Martin Petermann
* Sven Schuetz
[SCSI] zfcp: status read buffers on first adapter open with link down Commit 64deb6efdc5504ce97b5c1c6f281fffbc150bd93 "[SCSI] zfcp: Use status_read_buf_num provided by FCP channel" started using a value returned by the channel but only evaluated the value if the fabric link is up. Commit 8d88cf3f3b9af4713642caeb221b6d6a42019001 "[SCSI] zfcp: Update status read mempool" introduced mempool resizings based on the above value. On setting an FCP device online for the very first time since boot, a new zeroed adapter object is allocated. If the link is down, the number of status read requests remains zero. Since just the config data exchange is incomplete, we proceed with adapter open recovery. However, we unconditionally call mempool_resize with adapter->stat_read_buf_num == 0 in this case. This causes a kernel message "kernel BUG at mm/mempool.c:131!" in process "zfcperp<FCP-device-bus-ID>" with last function mempool_resize in Krnl PSW and zfcp_erp_thread in the Call Trace. Don't evaluate channel values which are invalid on link down. The number of status read requests is always valid, evaluated, and set to a positive minimum greater than zero. The adapter open recovery can proceed and the channel has status read buffers to inform us on a future link up event. While we are not aware of any other code path that could result in mempool resize attempts of size zero, we still also initialize the number of status read buffers to be posted to a static minimum number on adapter object allocation. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> #2.6.35+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-04-26 23:34:54 +08:00
* Steffen Maier
*/
#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/miscdevice.h>
#include <linux/seq_file.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/module.h>
#include "zfcp_ext.h"
#include "zfcp_fc.h"
#include "zfcp_reqlist.h"
#define ZFCP_BUS_ID_SIZE 20
MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
MODULE_DESCRIPTION("FCP HBA driver");
MODULE_LICENSE("GPL");
static char *init_device;
module_param_named(device, init_device, charp, 0400);
MODULE_PARM_DESC(device, "specify initial device");
static struct kmem_cache * __init zfcp_cache_hw_align(const char *name,
unsigned long size)
{
return kmem_cache_create(name, size, roundup_pow_of_two(size), 0, NULL);
}
static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
{
struct ccw_device *cdev;
struct zfcp_adapter *adapter;
struct zfcp_port *port;
cdev = get_ccwdev_by_busid(&zfcp_ccw_driver, busid);
if (!cdev)
return;
if (ccw_device_set_online(cdev))
goto out_ccw_device;
adapter = zfcp_ccw_adapter_by_cdev(cdev);
if (!adapter)
goto out_ccw_device;
port = zfcp_get_port_by_wwpn(adapter, wwpn);
if (!port)
goto out_port;
flush_work(&port->rport_work);
zfcp_unit_add(port, lun);
put_device(&port->dev);
out_port:
zfcp_ccw_adapter_put(adapter);
out_ccw_device:
put_device(&cdev->dev);
return;
}
static void __init zfcp_init_device_setup(char *devstr)
{
char *token;
char *str, *str_saved;
char busid[ZFCP_BUS_ID_SIZE];
u64 wwpn, lun;
/* duplicate devstr and keep the original for sysfs presentation*/
str_saved = kstrdup(devstr, GFP_KERNEL);
str = str_saved;
if (!str)
return;
token = strsep(&str, ",");
if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
goto err_out;
strncpy(busid, token, ZFCP_BUS_ID_SIZE);
token = strsep(&str, ",");
if (!token || kstrtoull(token, 0, (unsigned long long *) &wwpn))
goto err_out;
token = strsep(&str, ",");
if (!token || kstrtoull(token, 0, (unsigned long long *) &lun))
goto err_out;
kfree(str_saved);
zfcp_init_device_configure(busid, wwpn, lun);
return;
err_out:
kfree(str_saved);
pr_err("%s is not a valid SCSI device\n", devstr);
}
static int __init zfcp_module_init(void)
{
int retval = -ENOMEM;
zfcp_fsf_qtcb_cache = zfcp_cache_hw_align("zfcp_fsf_qtcb",
sizeof(struct fsf_qtcb));
if (!zfcp_fsf_qtcb_cache)
goto out_qtcb_cache;
zfcp_fc_req_cache = zfcp_cache_hw_align("zfcp_fc_req",
sizeof(struct zfcp_fc_req));
if (!zfcp_fc_req_cache)
goto out_fc_cache;
zfcp_scsi_transport_template =
fc_attach_transport(&zfcp_transport_functions);
if (!zfcp_scsi_transport_template)
goto out_transport;
scsi_transport_reserve_device(zfcp_scsi_transport_template,
sizeof(struct zfcp_scsi_dev));
retval = ccw_driver_register(&zfcp_ccw_driver);
if (retval) {
pr_err("The zfcp device driver could not register with "
"the common I/O layer\n");
goto out_ccw_register;
}
if (init_device)
zfcp_init_device_setup(init_device);
return 0;
out_ccw_register:
fc_release_transport(zfcp_scsi_transport_template);
out_transport:
kmem_cache_destroy(zfcp_fc_req_cache);
out_fc_cache:
kmem_cache_destroy(zfcp_fsf_qtcb_cache);
out_qtcb_cache:
return retval;
}
module_init(zfcp_module_init);
static void __exit zfcp_module_exit(void)
{
ccw_driver_unregister(&zfcp_ccw_driver);
fc_release_transport(zfcp_scsi_transport_template);
kmem_cache_destroy(zfcp_fc_req_cache);
kmem_cache_destroy(zfcp_fsf_qtcb_cache);
}
module_exit(zfcp_module_exit);
/**
* zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
* @adapter: pointer to adapter to search for port
* @wwpn: wwpn to search for
*
* Returns: pointer to zfcp_port or NULL
*/
struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
u64 wwpn)
{
unsigned long flags;
struct zfcp_port *port;
read_lock_irqsave(&adapter->port_list_lock, flags);
list_for_each_entry(port, &adapter->port_list, list)
if (port->wwpn == wwpn) {
if (!get_device(&port->dev))
port = NULL;
read_unlock_irqrestore(&adapter->port_list_lock, flags);
return port;
}
read_unlock_irqrestore(&adapter->port_list_lock, flags);
return NULL;
}
static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
{
adapter->pool.erp_req =
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
if (!adapter->pool.erp_req)
return -ENOMEM;
adapter->pool.gid_pn_req =
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
if (!adapter->pool.gid_pn_req)
return -ENOMEM;
adapter->pool.scsi_req =
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
if (!adapter->pool.scsi_req)
return -ENOMEM;
adapter->pool.scsi_abort =
mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
if (!adapter->pool.scsi_abort)
return -ENOMEM;
adapter->pool.status_read_req =
mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
sizeof(struct zfcp_fsf_req));
if (!adapter->pool.status_read_req)
return -ENOMEM;
adapter->pool.qtcb_pool =
mempool_create_slab_pool(4, zfcp_fsf_qtcb_cache);
if (!adapter->pool.qtcb_pool)
return -ENOMEM;
BUILD_BUG_ON(sizeof(struct fsf_status_read_buffer) > PAGE_SIZE);
adapter->pool.sr_data =
mempool_create_page_pool(FSF_STATUS_READS_RECOM, 0);
if (!adapter->pool.sr_data)
return -ENOMEM;
adapter->pool.gid_pn =
mempool_create_slab_pool(1, zfcp_fc_req_cache);
if (!adapter->pool.gid_pn)
return -ENOMEM;
return 0;
}
static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
{
if (adapter->pool.erp_req)
mempool_destroy(adapter->pool.erp_req);
if (adapter->pool.scsi_req)
mempool_destroy(adapter->pool.scsi_req);
if (adapter->pool.scsi_abort)
mempool_destroy(adapter->pool.scsi_abort);
if (adapter->pool.qtcb_pool)
mempool_destroy(adapter->pool.qtcb_pool);
if (adapter->pool.status_read_req)
mempool_destroy(adapter->pool.status_read_req);
if (adapter->pool.sr_data)
mempool_destroy(adapter->pool.sr_data);
if (adapter->pool.gid_pn)
mempool_destroy(adapter->pool.gid_pn);
}
/**
* zfcp_status_read_refill - refill the long running status_read_requests
* @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
*
* Returns: 0 on success, 1 otherwise
*
* if there are 16 or more status_read requests missing an adapter_reopen
* is triggered
*/
int zfcp_status_read_refill(struct zfcp_adapter *adapter)
{
while (atomic_read(&adapter->stat_miss) > 0)
if (zfcp_fsf_status_read(adapter->qdio)) {
if (atomic_read(&adapter->stat_miss) >=
adapter->stat_read_buf_num) {
zfcp_erp_adapter_reopen(adapter, 0, "axsref1");
return 1;
}
break;
} else
atomic_dec(&adapter->stat_miss);
return 0;
}
static void _zfcp_status_read_scheduler(struct work_struct *work)
{
zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
stat_work));
}
static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
{
struct zfcp_adapter *adapter =
container_of(sl, struct zfcp_adapter, service_level);
seq_printf(m, "zfcp: %s microcode level %x\n",
dev_name(&adapter->ccw_device->dev),
adapter->fsf_lic_version);
}
static int zfcp_setup_adapter_work_queue(struct zfcp_adapter *adapter)
{
char name[TASK_COMM_LEN];
snprintf(name, sizeof(name), "zfcp_q_%s",
dev_name(&adapter->ccw_device->dev));
adapter->work_queue = create_singlethread_workqueue(name);
if (adapter->work_queue)
return 0;
return -ENOMEM;
}
static void zfcp_destroy_adapter_work_queue(struct zfcp_adapter *adapter)
{
if (adapter->work_queue)
destroy_workqueue(adapter->work_queue);
adapter->work_queue = NULL;
}
/**
* zfcp_adapter_enqueue - enqueue a new adapter to the list
* @ccw_device: pointer to the struct cc_device
*
* Returns: struct zfcp_adapter*
* Enqueues an adapter at the end of the adapter list in the driver data.
* All adapter internal structures are set up.
* Proc-fs entries are also created.
*/
struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
{
struct zfcp_adapter *adapter;
if (!get_device(&ccw_device->dev))
return ERR_PTR(-ENODEV);
adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
if (!adapter) {
put_device(&ccw_device->dev);
return ERR_PTR(-ENOMEM);
}
kref_init(&adapter->ref);
ccw_device->handler = NULL;
adapter->ccw_device = ccw_device;
INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
zfcp: auto port scan resiliency This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-13 21:59:48 +08:00
INIT_DELAYED_WORK(&adapter->scan_work, zfcp_fc_scan_ports);
INIT_WORK(&adapter->ns_up_work, zfcp_fc_sym_name_update);
zfcp: auto port scan resiliency This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-13 21:59:48 +08:00
adapter->next_port_scan = jiffies;
if (zfcp_qdio_setup(adapter))
goto failed;
if (zfcp_allocate_low_mem_buffers(adapter))
goto failed;
adapter->req_list = zfcp_reqlist_alloc();
if (!adapter->req_list)
goto failed;
if (zfcp_dbf_adapter_register(adapter))
goto failed;
if (zfcp_setup_adapter_work_queue(adapter))
goto failed;
if (zfcp_fc_gs_setup(adapter))
goto failed;
rwlock_init(&adapter->port_list_lock);
INIT_LIST_HEAD(&adapter->port_list);
INIT_LIST_HEAD(&adapter->events.list);
INIT_WORK(&adapter->events.work, zfcp_fc_post_event);
spin_lock_init(&adapter->events.list_lock);
init_waitqueue_head(&adapter->erp_ready_wq);
init_waitqueue_head(&adapter->erp_done_wqh);
INIT_LIST_HEAD(&adapter->erp_ready_head);
INIT_LIST_HEAD(&adapter->erp_running_head);
rwlock_init(&adapter->erp_lock);
rwlock_init(&adapter->abort_lock);
if (zfcp_erp_thread_setup(adapter))
goto failed;
adapter->service_level.seq_print = zfcp_print_sl;
dev_set_drvdata(&ccw_device->dev, adapter);
if (sysfs_create_group(&ccw_device->dev.kobj,
&zfcp_sysfs_adapter_attrs))
goto failed;
/* report size limit per scatter-gather segment */
adapter->dma_parms.max_segment_size = ZFCP_QDIO_SBALE_LEN;
adapter->ccw_device->dev.dma_parms = &adapter->dma_parms;
[SCSI] zfcp: status read buffers on first adapter open with link down Commit 64deb6efdc5504ce97b5c1c6f281fffbc150bd93 "[SCSI] zfcp: Use status_read_buf_num provided by FCP channel" started using a value returned by the channel but only evaluated the value if the fabric link is up. Commit 8d88cf3f3b9af4713642caeb221b6d6a42019001 "[SCSI] zfcp: Update status read mempool" introduced mempool resizings based on the above value. On setting an FCP device online for the very first time since boot, a new zeroed adapter object is allocated. If the link is down, the number of status read requests remains zero. Since just the config data exchange is incomplete, we proceed with adapter open recovery. However, we unconditionally call mempool_resize with adapter->stat_read_buf_num == 0 in this case. This causes a kernel message "kernel BUG at mm/mempool.c:131!" in process "zfcperp<FCP-device-bus-ID>" with last function mempool_resize in Krnl PSW and zfcp_erp_thread in the Call Trace. Don't evaluate channel values which are invalid on link down. The number of status read requests is always valid, evaluated, and set to a positive minimum greater than zero. The adapter open recovery can proceed and the channel has status read buffers to inform us on a future link up event. While we are not aware of any other code path that could result in mempool resize attempts of size zero, we still also initialize the number of status read buffers to be posted to a static minimum number on adapter object allocation. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> #2.6.35+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-04-26 23:34:54 +08:00
adapter->stat_read_buf_num = FSF_STATUS_READS_RECOM;
if (!zfcp_scsi_adapter_register(adapter))
return adapter;
failed:
zfcp_adapter_unregister(adapter);
return ERR_PTR(-ENOMEM);
}
void zfcp_adapter_unregister(struct zfcp_adapter *adapter)
{
struct ccw_device *cdev = adapter->ccw_device;
zfcp: auto port scan resiliency This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-13 21:59:48 +08:00
cancel_delayed_work_sync(&adapter->scan_work);
cancel_work_sync(&adapter->stat_work);
cancel_work_sync(&adapter->ns_up_work);
zfcp_destroy_adapter_work_queue(adapter);
zfcp_fc_wka_ports_force_offline(adapter->gs);
zfcp_scsi_adapter_unregister(adapter);
sysfs_remove_group(&cdev->dev.kobj, &zfcp_sysfs_adapter_attrs);
zfcp_erp_thread_kill(adapter);
zfcp_dbf_adapter_unregister(adapter);
zfcp_qdio_destroy(adapter->qdio);
zfcp_ccw_adapter_put(adapter); /* final put to release */
}
/**
* zfcp_adapter_release - remove the adapter from the resource list
* @ref: pointer to struct kref
* locks: adapter list write lock is assumed to be held by caller
*/
void zfcp_adapter_release(struct kref *ref)
{
struct zfcp_adapter *adapter = container_of(ref, struct zfcp_adapter,
ref);
struct ccw_device *cdev = adapter->ccw_device;
dev_set_drvdata(&adapter->ccw_device->dev, NULL);
zfcp_fc_gs_destroy(adapter);
zfcp_free_low_mem_buffers(adapter);
kfree(adapter->req_list);
kfree(adapter->fc_stats);
kfree(adapter->stats_reset_data);
kfree(adapter);
put_device(&cdev->dev);
}
static void zfcp_port_release(struct device *dev)
{
struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
zfcp_ccw_adapter_put(port->adapter);
kfree(port);
}
/**
* zfcp_port_enqueue - enqueue port to port list of adapter
* @adapter: adapter where remote port is added
* @wwpn: WWPN of the remote port to be enqueued
* @status: initial status for the port
* @d_id: destination id of the remote port to be enqueued
* Returns: pointer to enqueued port on success, ERR_PTR on error
*
* All port internal structures are set up and the sysfs entry is generated.
* d_id is used to enqueue ports with a well known address like the Directory
* Service for nameserver lookup.
*/
struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
u32 status, u32 d_id)
{
struct zfcp_port *port;
int retval = -ENOMEM;
kref_get(&adapter->ref);
port = zfcp_get_port_by_wwpn(adapter, wwpn);
if (port) {
put_device(&port->dev);
retval = -EEXIST;
goto err_out;
}
port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
if (!port)
goto err_out;
rwlock_init(&port->unit_list_lock);
INIT_LIST_HEAD(&port->unit_list);
atomic_set(&port->units, 0);
INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);
port->adapter = adapter;
port->d_id = d_id;
port->wwpn = wwpn;
port->rport_task = RPORT_NONE;
port->dev.parent = &adapter->ccw_device->dev;
port->dev.groups = zfcp_port_attr_groups;
port->dev.release = zfcp_port_release;
if (dev_set_name(&port->dev, "0x%016llx", (unsigned long long)wwpn)) {
kfree(port);
goto err_out;
}
retval = -EINVAL;
if (device_register(&port->dev)) {
put_device(&port->dev);
goto err_out;
}
write_lock_irq(&adapter->port_list_lock);
list_add_tail(&port->list, &adapter->port_list);
write_unlock_irq(&adapter->port_list_lock);
atomic_set_mask(status | ZFCP_STATUS_COMMON_RUNNING, &port->status);
return port;
err_out:
zfcp_ccw_adapter_put(adapter);
return ERR_PTR(retval);
}
/**
* zfcp_sg_free_table - free memory used by scatterlists
* @sg: pointer to scatterlist
* @count: number of scatterlist which are to be free'ed
* the scatterlist are expected to reference pages always
*/
void zfcp_sg_free_table(struct scatterlist *sg, int count)
{
int i;
for (i = 0; i < count; i++, sg++)
if (sg)
free_page((unsigned long) sg_virt(sg));
else
break;
}
/**
* zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
* @sg: pointer to struct scatterlist
* @count: number of scatterlists which should be assigned with buffers
* of size page
*
* Returns: 0 on success, -ENOMEM otherwise
*/
int zfcp_sg_setup_table(struct scatterlist *sg, int count)
{
void *addr;
int i;
sg_init_table(sg, count);
for (i = 0; i < count; i++, sg++) {
addr = (void *) get_zeroed_page(GFP_KERNEL);
if (!addr) {
zfcp_sg_free_table(sg, i);
return -ENOMEM;
}
sg_set_buf(sg, addr, PAGE_SIZE);
}
return 0;
}