dm: fix potential for q->make_request_fn NULL pointer

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c752c55..c4d4cd3 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2293,7 +2293,6 @@ static void dm_init_md_queue(struct mapped_device *md)
         * - must do so here (in alloc_dev callchain) before queue is used
         */
        md->queue->queuedata = md;
-       md->queue->backing_dev_info.congested_data = md;
 }
 
 static void dm_init_old_md_queue(struct mapped_device *md)
@@ -2304,6 +2303,7 @@ static void dm_init_old_md_queue(struct mapped_device *md)
        /*
         * Initialize aspects of queue that aren't relevant for blk-mq
         */
+       md->queue->backing_dev_info.congested_data = md;
        md->queue->backing_dev_info.congested_fn = dm_any_congested;
        blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
 }
@@ -2386,6 +2386,12 @@ static struct mapped_device *alloc_dev(int minor)
                goto bad;
 
        dm_init_md_queue(md);
+       /*
+        * default to bio-based required ->make_request_fn until DM
+        * table is loaded and md->type established. If request-based
+        * table is loaded: blk-mq will override accordingly.
+        */
+       blk_queue_make_request(md->queue, dm_make_request);
 
        md->disk = alloc_disk(1);
        if (!md->disk)
@@ -2849,7 +2855,6 @@ int dm_setup_md_queue(struct mapped_device *md)
                break;
        case DM_TYPE_BIO_BASED:
                dm_init_old_md_queue(md);
-               blk_queue_make_request(md->queue, dm_make_request);
                /*
                 * DM handles splitting bios as needed.  Free the bio_split bioset
                 * since it won't be used (saves 1 process per bio-based DM device).