From: Mike Snitzer <snitzer@xxxxxxxxxx> commit 47ace7e012b9f7ad71d43ac9063d335ea3d6820b upstream. Move blk_queue_make_request() to dm.c:alloc_dev() so that q->make_request_fn is never NULL during the lifetime of a DM device (even one that is created without a DM table). Otherwise generic_make_request() will crash simply by doing: dmsetup create -n test mount /dev/dm-N /mnt While at it, move ->congested_data initialization out of dm.c:alloc_dev() and into the bio-based specific init method. Reported-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx> BugLink: https://bugs.launchpad.net/bugs/1860231 Fixes: ff36ab34583a ("dm: remove request-based logic from make_request_fn wrapper") Depends-on: c12c9a3c3860c ("dm: various cleanups to md->queue initialization code") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> [smb: adjusted for context and dm_init_md_queue() exitsting in older kernels] Signed-off-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1647,7 +1647,6 @@ void dm_init_md_queue(struct mapped_devi * - must do so here (in alloc_dev callchain) before queue is used */ md->queue->queuedata = md; - md->queue->backing_dev_info->congested_data = md; } void dm_init_normal_md_queue(struct mapped_device *md) @@ -1658,6 +1657,7 @@ void dm_init_normal_md_queue(struct mapp /* * 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; } @@ -1750,6 +1750,12 @@ static struct mapped_device *alloc_dev(i 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_node(1, numa_node_id); if (!md->disk) @@ -2055,7 +2061,6 @@ int dm_setup_md_queue(struct mapped_devi case DM_TYPE_BIO_BASED: case DM_TYPE_DAX_BIO_BASED: dm_init_normal_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).
