block: force noio scope in blk_mq_freeze_queue

When block drivers or the core block code perform allocations with a
frozen queue, this could try to recurse into the block device to
reclaim memory and deadlock.  Thus all allocations done by a process
that froze a queue need to be done without __GFP_IO and __GFP_FS.
Instead of tying to track all of them down, force a noio scope as
part of freezing the queue.

Note that nvme is a bit of a mess here due to the non-owner freezes,
and they will be addressed separately.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250131120352.1315351-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5b393e4a1ddf..faafd7ff43d6 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -7281,9 +7281,10 @@ static ssize_t do_rbd_remove(const char *buf, size_t count)
 		 * Prevent new IO from being queued and wait for existing
 		 * IO to complete/fail.
 		 */
-		blk_mq_freeze_queue(rbd_dev->disk->queue);
+		unsigned int memflags = blk_mq_freeze_queue(rbd_dev->disk->queue);
+
 		blk_mark_disk_dead(rbd_dev->disk);
-		blk_mq_unfreeze_queue(rbd_dev->disk->queue);
+		blk_mq_unfreeze_queue(rbd_dev->disk->queue, memflags);
 	}
 
 	del_gendisk(rbd_dev->disk);