1 files changed, 72 insertions, 39 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index e81345a1d08f..826bce7343b3 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -69,6 +69,7 @@ struct multipath {
         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 */
+        wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
 
         unsigned nr_valid_paths;        /* Total number of usable paths */
         struct pgpath *current_pgpath;
@@ -95,8 +96,6 @@ struct multipath {
         mempool_t *mpio_pool;
 
         struct mutex work_mutex;
-
-        unsigned suspended;     /* Don't create new I/O internally when set. */
 };
 
 /*
@@ -202,6 +201,7 @@ 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_waitqueue_head(&m->pg_init_wait);
                 mutex_init(&m->work_mutex);
                 m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
                 if (!m->mpio_pool) {
@@ -235,6 +235,21 @@ static void free_multipath(struct multipath *m)
  * Path selection
  *-----------------------------------------------*/
 
+static void __pg_init_all_paths(struct multipath *m)
+{
+        struct pgpath *pgpath;
+
+        m->pg_init_count++;
+        m->pg_init_required = 0;
+        list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) {
+                /* Skip failed paths */
+                if (!pgpath->is_active)
+                        continue;
+                if (queue_work(kmpath_handlerd, &pgpath->activate_path))
+                        m->pg_init_in_progress++;
+        }
+}
+
 static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
 {
         m->current_pg = pgpath->pg;
@@ -439,7 +454,7 @@ static void process_queued_ios(struct work_struct *work)
 {
         struct multipath *m =
                 container_of(work, struct multipath, process_queued_ios);
-        struct pgpath *pgpath = NULL, *tmp;
+        struct pgpath *pgpath = NULL;
         unsigned must_queue = 1;
         unsigned long flags;
 
@@ -457,14 +472,9 @@ static void process_queued_ios(struct work_struct *work)
             (!pgpath && !m->queue_if_no_path))
                 must_queue = 0;
 
-        if (m->pg_init_required && !m->pg_init_in_progress && pgpath) {
-                m->pg_init_count++;
-                m->pg_init_required = 0;
-                list_for_each_entry(tmp, &pgpath->pg->pgpaths, list) {
-                        if (queue_work(kmpath_handlerd, &tmp->activate_path))
-                                m->pg_init_in_progress++;
-                }
-        }
+        if (m->pg_init_required && !m->pg_init_in_progress && pgpath)
+                __pg_init_all_paths(m);
+
 out:
         spin_unlock_irqrestore(&m->lock, flags);
         if (!must_queue)
@@ -597,8 +607,8 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
         if (!p)
                 return ERR_PTR(-ENOMEM);
 
-        r = dm_get_device(ti, shift(as), ti->begin, ti->len,
-                          dm_table_get_mode(ti->table), &p->path.dev);
+        r = dm_get_device(ti, shift(as), dm_table_get_mode(ti->table),
+                          &p->path.dev);
         if (r) {
                 ti->error = "error getting device";
                 goto bad;
@@ -890,9 +900,34 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
         return r;
 }
 
-static void flush_multipath_work(void)
+static void multipath_wait_for_pg_init_completion(struct multipath *m)
+{
+        DECLARE_WAITQUEUE(wait, current);
+        unsigned long flags;
+
+        add_wait_queue(&m->pg_init_wait, &wait);
+
+        while (1) {
+                set_current_state(TASK_UNINTERRUPTIBLE);
+
+                spin_lock_irqsave(&m->lock, flags);
+                if (!m->pg_init_in_progress) {
+                        spin_unlock_irqrestore(&m->lock, flags);
+                        break;
+                }
+                spin_unlock_irqrestore(&m->lock, flags);
+
+                io_schedule();
+        }
+        set_current_state(TASK_RUNNING);
+
+        remove_wait_queue(&m->pg_init_wait, &wait);
+}
+
+static void flush_multipath_work(struct multipath *m)
 {
         flush_workqueue(kmpath_handlerd);
+        multipath_wait_for_pg_init_completion(m);
         flush_workqueue(kmultipathd);
         flush_scheduled_work();
 }
@@ -901,7 +936,7 @@ static void multipath_dtr(struct dm_target *ti)
 {
         struct multipath *m = ti->private;
 
-        flush_multipath_work();
+        flush_multipath_work(m);
         free_multipath(m);
 }
 
@@ -1128,8 +1163,7 @@ static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
 
 static void pg_init_done(void *data, int errors)
 {
-        struct dm_path *path = data;
-        struct pgpath *pgpath = path_to_pgpath(path);
+        struct pgpath *pgpath = data;
         struct priority_group *pg = pgpath->pg;
         struct multipath *m = pg->m;
         unsigned long flags;
@@ -1143,8 +1177,8 @@ static void pg_init_done(void *data, int errors)
                         errors = 0;
                         break;
                 }
-                DMERR("Cannot failover device because scsi_dh_%s was not "
-                      "loaded.", m->hw_handler_name);
+                DMERR("Could not failover the device: Handler scsi_dh_%s "
+                      "Error %d.", m->hw_handler_name, errors);
                 /*
                  * Fail path for now, so we do not ping pong
                  */
@@ -1181,14 +1215,24 @@ static void pg_init_done(void *data, int errors)
                         m->current_pgpath = NULL;
                         m->current_pg = NULL;
                 }
-        } else if (!m->pg_init_required) {
-                m->queue_io = 0;
+        } else if (!m->pg_init_required)
                 pg->bypassed = 0;
-        }
 
-        m->pg_init_in_progress--;
-        if (!m->pg_init_in_progress)
-                queue_work(kmultipathd, &m->process_queued_ios);
+        if (--m->pg_init_in_progress)
+                /* Activations of other paths are still on going */
+                goto out;
+
+        if (!m->pg_init_required)
+                m->queue_io = 0;
+
+        queue_work(kmultipathd, &m->process_queued_ios);
+
+        /*
+         * Wake up any thread waiting to suspend.
+         */
+        wake_up(&m->pg_init_wait);
+
+out:
         spin_unlock_irqrestore(&m->lock, flags);
 }
 
@@ -1198,7 +1242,7 @@ static void activate_path(struct work_struct *work)
                 container_of(work, struct pgpath, activate_path);
 
         scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
-                                pg_init_done, &pgpath->path);
+                                pg_init_done, pgpath);
 }
 
 /*
@@ -1276,8 +1320,7 @@ static void multipath_postsuspend(struct dm_target *ti)
         struct multipath *m = ti->private;
 
         mutex_lock(&m->work_mutex);
-        m->suspended = 1;
-        flush_multipath_work();
+        flush_multipath_work(m);
         mutex_unlock(&m->work_mutex);
 }
 
@@ -1289,10 +1332,6 @@ static void multipath_resume(struct dm_target *ti)
         struct multipath *m = (struct multipath *) ti->private;
         unsigned long flags;
 
-        mutex_lock(&m->work_mutex);
-        m->suspended = 0;
-        mutex_unlock(&m->work_mutex);
-
         spin_lock_irqsave(&m->lock, flags);
         m->queue_if_no_path = m->saved_queue_if_no_path;
         spin_unlock_irqrestore(&m->lock, flags);
@@ -1428,11 +1467,6 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
 
         mutex_lock(&m->work_mutex);
 
-        if (m->suspended) {
-                r = -EBUSY;
-                goto out;
-        }
-
         if (dm_suspended(ti)) {
                 r = -EBUSY;
                 goto out;
@@ -1471,8 +1505,7 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
                 goto out;
         }
 
-        r = dm_get_device(ti, argv[1], ti->begin, ti->len,
-                          dm_table_get_mode(ti->table), &dev);
+        r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev);
         if (r) {
                 DMWARN("message: error getting device %s",
                        argv[1]);