1 files changed, 37 insertions, 10 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 73f28802dc7a..8001fe9e3434 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -433,7 +433,6 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 
         dm_get(md);
         atomic_inc(&md->open_count);
-
 out:
         spin_unlock(&_minor_lock);
 
@@ -442,16 +441,20 @@ out:
 
 static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 {
-        struct mapped_device *md = disk->private_data;
+        struct mapped_device *md;
 
         spin_lock(&_minor_lock);
 
+        md = disk->private_data;
+        if (WARN_ON(!md))
+                goto out;
+
         if (atomic_dec_and_test(&md->open_count) &&
             (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
                 queue_work(deferred_remove_workqueue, &deferred_remove_work);
 
         dm_put(md);
-
+out:
         spin_unlock(&_minor_lock);
 }
 
@@ -2241,7 +2244,6 @@ static void free_dev(struct mapped_device *md)
         int minor = MINOR(disk_devt(md->disk));
 
         unlock_fs(md);
-        bdput(md->bdev);
         destroy_workqueue(md->wq);
 
         if (md->kworker_task)
@@ -2252,19 +2254,22 @@ static void free_dev(struct mapped_device *md)
                 mempool_destroy(md->rq_pool);
         if (md->bs)
                 bioset_free(md->bs);
-        blk_integrity_unregister(md->disk);
-        del_gendisk(md->disk);
+
         cleanup_srcu_struct(&md->io_barrier);
         free_table_devices(&md->table_devices);
-        free_minor(minor);
+        dm_stats_cleanup(&md->stats);
 
         spin_lock(&_minor_lock);
         md->disk->private_data = NULL;
         spin_unlock(&_minor_lock);
-
+        if (blk_get_integrity(md->disk))
+                blk_integrity_unregister(md->disk);
+        del_gendisk(md->disk);
         put_disk(md->disk);
         blk_cleanup_queue(md->queue);
-        dm_stats_cleanup(&md->stats);
+        bdput(md->bdev);
+        free_minor(minor);
+
         module_put(THIS_MODULE);
         kfree(md);
 }
@@ -2616,6 +2621,19 @@ void dm_get(struct mapped_device *md)
         BUG_ON(test_bit(DMF_FREEING, &md->flags));
 }
 
+int dm_hold(struct mapped_device *md)
+{
+        spin_lock(&_minor_lock);
+        if (test_bit(DMF_FREEING, &md->flags)) {
+                spin_unlock(&_minor_lock);
+                return -EBUSY;
+        }
+        dm_get(md);
+        spin_unlock(&_minor_lock);
+        return 0;
+}
+EXPORT_SYMBOL_GPL(dm_hold);
+
 const char *dm_device_name(struct mapped_device *md)
 {
         return md->name;
@@ -2629,8 +2647,9 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 
         might_sleep();
 
-        spin_lock(&_minor_lock);
         map = dm_get_live_table(md, &srcu_idx);
+
+        spin_lock(&_minor_lock);
         idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
         set_bit(DMF_FREEING, &md->flags);
         spin_unlock(&_minor_lock);
@@ -2638,10 +2657,16 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
         if (dm_request_based(md))
                 flush_kthread_worker(&md->kworker);
 
+        /*
+         * Take suspend_lock so that presuspend and postsuspend methods
+         * do not race with internal suspend.
+         */
+        mutex_lock(&md->suspend_lock);
         if (!dm_suspended_md(md)) {
                 dm_table_presuspend_targets(map);
                 dm_table_postsuspend_targets(map);
         }
+        mutex_unlock(&md->suspend_lock);
 
         /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
         dm_put_live_table(md, srcu_idx);
@@ -3115,6 +3140,7 @@ void dm_internal_suspend_fast(struct mapped_device *md)
         flush_workqueue(md->wq);
         dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
 }
+EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
 
 void dm_internal_resume_fast(struct mapped_device *md)
 {
@@ -3126,6 +3152,7 @@ void dm_internal_resume_fast(struct mapped_device *md)
 done:
         mutex_unlock(&md->suspend_lock);
 }
+EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
 
 /*-----------------------------------------------------------------
  * Event notification.