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-rw-r--r--drivers/md/dm-mpath.c41
1 files changed, 34 insertions, 7 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index e54ff372d711..9b16788118d2 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -63,6 +63,7 @@ struct multipath {
spinlock_t lock;
const char *hw_handler_name;
+ struct work_struct activate_path;
unsigned nr_priority_groups;
struct list_head priority_groups;
unsigned pg_init_required; /* pg_init needs calling? */
@@ -107,10 +108,10 @@ typedef int (*action_fn) (struct pgpath *pgpath);
static struct kmem_cache *_mpio_cache;
-static struct workqueue_struct *kmultipathd;
+static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
static void process_queued_ios(struct work_struct *work);
static void trigger_event(struct work_struct *work);
-static void pg_init_done(struct dm_path *, int);
+static void activate_path(struct work_struct *work);
/*-----------------------------------------------
@@ -180,6 +181,7 @@ 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);
m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
@@ -432,11 +434,8 @@ static void process_queued_ios(struct work_struct *work)
out:
spin_unlock_irqrestore(&m->lock, flags);
- if (init_required) {
- struct dm_path *path = &pgpath->path;
- int ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
- pg_init_done(path, ret);
- }
+ if (init_required)
+ queue_work(kmpath_handlerd, &m->activate_path);
if (!must_queue)
dispatch_queued_ios(m);
@@ -791,6 +790,7 @@ static void multipath_dtr(struct dm_target *ti)
{
struct multipath *m = (struct multipath *) ti->private;
+ flush_workqueue(kmpath_handlerd);
flush_workqueue(kmultipathd);
free_multipath(m);
}
@@ -1108,6 +1108,17 @@ static void pg_init_done(struct dm_path *path, int errors)
spin_unlock_irqrestore(&m->lock, flags);
}
+static void activate_path(struct work_struct *work)
+{
+ int ret;
+ struct multipath *m =
+ container_of(work, struct multipath, activate_path);
+ struct dm_path *path = &m->current_pgpath->path;
+
+ ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
+ pg_init_done(path, ret);
+}
+
/*
* end_io handling
*/
@@ -1451,6 +1462,21 @@ static int __init dm_multipath_init(void)
return -ENOMEM;
}
+ /*
+ * A separate workqueue is used to handle the device handlers
+ * to avoid overloading existing workqueue. Overloading the
+ * old workqueue would also create a bottleneck in the
+ * path of the storage hardware device activation.
+ */
+ kmpath_handlerd = create_singlethread_workqueue("kmpath_handlerd");
+ if (!kmpath_handlerd) {
+ DMERR("failed to create workqueue kmpath_handlerd");
+ destroy_workqueue(kmultipathd);
+ dm_unregister_target(&multipath_target);
+ kmem_cache_destroy(_mpio_cache);
+ return -ENOMEM;
+ }
+
DMINFO("version %u.%u.%u loaded",
multipath_target.version[0], multipath_target.version[1],
multipath_target.version[2]);
@@ -1462,6 +1488,7 @@ static void __exit dm_multipath_exit(void)
{
int r;
+ destroy_workqueue(kmpath_handlerd);
destroy_workqueue(kmultipathd);
r = dm_unregister_target(&multipath_target);