[dm-devel] [PATCH] dm mpath: delay retry activate_path on SCSI_DH_RETRY
Nikanth Karthikesan
knikanth at suse.de
Tue Feb 17 13:47:37 UTC 2009
Delay retry to activate_path if it returns SCSI_DH_RETRY.
Signed-off-by: Nikanth Karthikesan <knikanth at suse.de>
---
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 095f77b..af54632 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -65,12 +65,14 @@ struct multipath {
spinlock_t lock;
const char *hw_handler_name;
- struct work_struct activate_path;
+ struct delayed_work activate_path;
struct pgpath *pgpath_to_activate;
unsigned nr_priority_groups;
struct list_head priority_groups;
unsigned pg_init_required; /* pg_init needs calling? */
unsigned pg_init_in_progress; /* Only one pg_init allowed at once */
+ unsigned long pg_init_jiffy; /* To delay retry if SCSI_DH_RETRY */
+#define SCSI_DH_RETRY_DELAY ((HZ * 2))
unsigned nr_valid_paths; /* Total number of usable paths */
struct pgpath *current_pgpath;
@@ -203,7 +205,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
m->queue_io = 1;
INIT_WORK(&m->process_queued_ios, process_queued_ios);
INIT_WORK(&m->trigger_event, trigger_event);
- INIT_WORK(&m->activate_path, activate_path);
+ INIT_DELAYED_WORK(&m->activate_path, activate_path);
m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
@@ -431,6 +433,8 @@ static void process_queued_ios(struct work_struct *work)
struct pgpath *pgpath = NULL;
unsigned init_required = 0, must_queue = 1;
unsigned long flags;
+ unsigned long delay = 0;
+ unsigned long now;
spin_lock_irqsave(&m->lock, flags);
@@ -452,13 +456,20 @@ static void process_queued_ios(struct work_struct *work)
m->pg_init_required = 0;
m->pg_init_in_progress = 1;
init_required = 1;
+ /* Delay retry due to SCSI_DH_RETRY */
+ if (m->pg_init_jiffy) {
+ now = jiffies;
+ if (time_after(now, m->pg_init_jiffy))
+ delay = now - m->pg_init_jiffy;
+ m->pg_init_jiffy = 0;
+ }
}
out:
spin_unlock_irqrestore(&m->lock, flags);
if (init_required)
- queue_work(kmpath_handlerd, &m->activate_path);
+ queue_delayed_work(kmpath_handlerd, &m->activate_path, delay);
if (!must_queue)
dispatch_queued_ios(m);
@@ -1060,6 +1071,7 @@ static void pg_init_done(struct dm_path *path, int errors)
struct priority_group *pg = pgpath->pg;
struct multipath *m = pg->m;
unsigned long flags;
+ bool delay = false;
/* device or driver problems */
switch (errors) {
@@ -1084,8 +1096,11 @@ static void pg_init_done(struct dm_path *path, int errors)
*/
bypass_pg(m, pg, 1);
break;
- /* TODO: For SCSI_DH_RETRY we should wait a couple seconds */
+ /*
+ * For SCSI_DH_RETRY we wait for a couple seconds.
+ */
case SCSI_DH_RETRY:
+ delay = true;
case SCSI_DH_IMM_RETRY:
case SCSI_DH_RES_TEMP_UNAVAIL:
if (pg_init_limit_reached(m, pgpath))
@@ -1112,6 +1127,10 @@ static void pg_init_done(struct dm_path *path, int errors)
}
m->pg_init_in_progress = 0;
+ if (delay)
+ m->pg_init_jiffy = jiffies + SCSI_DH_RETRY_DELAY;
+ else
+ m->pg_init_jiffy = 0;
queue_work(kmultipathd, &m->process_queued_ios);
spin_unlock_irqrestore(&m->lock, flags);
}
@@ -1120,7 +1139,7 @@ static void activate_path(struct work_struct *work)
{
int ret;
struct multipath *m =
- container_of(work, struct multipath, activate_path);
+ container_of(work, struct multipath, activate_path.work);
struct dm_path *path;
unsigned long flags;
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