From: Mike Snitzer snitzer@redhat.com

[ Upstream commit 47ace7e012b9f7ad71d43ac9063d335ea3d6820b ] 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@canonical.com 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@vger.kernel.org Signed-off-by: Mike Snitzer snitzer@redhat.com [smb: adjusted for context and dm_init_md_queue() exitsting in older kernels, and congested_data embedded in backing_dev_info] Signed-off-by: Stefan Bader stefan.bader@canonical.com --- drivers/md/dm.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 36e6221fabab..dd154027adc9 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1457,7 +1457,6 @@ 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; }

void dm_init_normal_md_queue(struct mapped_device *md) @@ -1468,6 +1467,7 @@ void dm_init_normal_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); } @@ -1555,6 +1555,12 @@ 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_node(1, numa_node_id); if (!md->disk) @@ -1853,7 +1859,6 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) 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).