[PATCH] device-mapper multipath: Use private workqueue

dm-mpath.c needs to use a private workqueue (like other dm targets already do)
to avoid interfering with users of the default workqueue.

Signed-Off-By: Alasdair G Kergon <agk@redhat.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Lars Marowsky-Bree <lmb@suse.de>
Signed-off-by: <mikenc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 43763a0..1e97b3c 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -101,6 +101,7 @@ typedef int (*action_fn) (struct pgpath *pgpath);
 
 static kmem_cache_t *_mpio_cache;
 
+struct workqueue_struct *kmultipathd;
 static void process_queued_ios(void *data);
 static void trigger_event(void *data);
 
@@ -308,7 +309,7 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
                bio_list_add(&m->queued_ios, bio);
                m->queue_size++;
                if (m->pg_init_required || !m->queue_io)
-                       schedule_work(&m->process_queued_ios);
+                       queue_work(kmultipathd, &m->process_queued_ios);
                pgpath = NULL;
                r = 0;
        } else if (!pgpath)
@@ -334,7 +335,7 @@ static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)
 
        m->queue_if_no_path = queue_if_no_path;
        if (!m->queue_if_no_path)
-               schedule_work(&m->process_queued_ios);
+               queue_work(kmultipathd, &m->process_queued_ios);
 
        spin_unlock_irqrestore(&m->lock, flags);
 
@@ -800,7 +801,7 @@ static int fail_path(struct pgpath *pgpath)
        if (pgpath == m->current_pgpath)
                m->current_pgpath = NULL;
 
-       schedule_work(&m->trigger_event);
+       queue_work(kmultipathd, &m->trigger_event);
 
 out:
        spin_unlock_irqrestore(&m->lock, flags);
@@ -837,9 +838,9 @@ static int reinstate_path(struct pgpath *pgpath)
 
        m->current_pgpath = NULL;
        if (!m->nr_valid_paths++)
-               schedule_work(&m->process_queued_ios);
+               queue_work(kmultipathd, &m->process_queued_ios);
 
-       schedule_work(&m->trigger_event);
+       queue_work(kmultipathd, &m->trigger_event);
 
 out:
        spin_unlock_irqrestore(&m->lock, flags);
@@ -883,7 +884,7 @@ static void bypass_pg(struct multipath *m, struct priority_group *pg,
 
        spin_unlock_irqrestore(&m->lock, flags);
 
-       schedule_work(&m->trigger_event);
+       queue_work(kmultipathd, &m->trigger_event);
 }
 
 /*
@@ -913,7 +914,7 @@ static int switch_pg_num(struct multipath *m, const char *pgstr)
        }
        spin_unlock_irqrestore(&m->lock, flags);
 
-       schedule_work(&m->trigger_event);
+       queue_work(kmultipathd, &m->trigger_event);
        return 0;
 }
 
@@ -968,7 +969,7 @@ void dm_pg_init_complete(struct path *path, unsigned err_flags)
                m->current_pgpath = NULL;
                m->current_pg = NULL;
        }
-       schedule_work(&m->process_queued_ios);
+       queue_work(kmultipathd, &m->process_queued_ios);
        spin_unlock_irqrestore(&m->lock, flags);
 }
 
@@ -1018,7 +1019,7 @@ static int do_end_io(struct multipath *m, struct bio *bio,
        bio_list_add(&m->queued_ios, bio);
        m->queue_size++;
        if (!m->queue_io)
-               schedule_work(&m->process_queued_ios);
+               queue_work(kmultipathd, &m->process_queued_ios);
        spin_unlock(&m->lock);
 
        return 1;       /* io not complete */
@@ -1057,7 +1058,7 @@ static void multipath_presuspend(struct dm_target *ti)
        spin_lock_irqsave(&m->lock, flags);
        m->suspended = 1;
        if (m->queue_if_no_path)
-               schedule_work(&m->process_queued_ios);
+               queue_work(kmultipathd, &m->process_queued_ios);
        spin_unlock_irqrestore(&m->lock, flags);
 }
 
@@ -1274,6 +1275,15 @@ static int __init dm_multipath_init(void)
                return -EINVAL;
        }
 
+       kmultipathd = create_workqueue("kmpathd");
+       if (!kmultipathd) {
+               DMERR("%s: failed to create workqueue kmpathd",
+                               multipath_target.name);
+               dm_unregister_target(&multipath_target);
+               kmem_cache_destroy(_mpio_cache);
+               return -ENOMEM;
+       }
+
        DMINFO("dm-multipath version %u.%u.%u loaded",
               multipath_target.version[0], multipath_target.version[1],
               multipath_target.version[2]);
@@ -1285,6 +1295,8 @@ static void __exit dm_multipath_exit(void)
 {
        int r;
 
+       destroy_workqueue(kmultipathd);
+
        r = dm_unregister_target(&multipath_target);
        if (r < 0)
                DMERR("%s: target unregister failed %d",