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authorChristoph Hellwig <hch@lst.de>2025-01-31 13:03:47 +0100
committerJens Axboe <axboe@kernel.dk>2025-01-31 07:20:08 -0700
commit1e1a9cecfab3f22ebef0a976f849c87be8d03c1c (patch)
tree34fa7958ed94c56127aa0fc55347bb409574af3a /block/blk-throttle.c
parent14ef49657ff3b7156952b2eadcf2e5bafd735795 (diff)
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>
Diffstat (limited to 'block/blk-throttle.c')
-rw-r--r--block/blk-throttle.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 82dbaefcfa3b..8d149aff9fd0 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1202,6 +1202,7 @@ static int blk_throtl_init(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct throtl_data *td;
+ unsigned int memflags;
int ret;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
@@ -1215,7 +1216,7 @@ static int blk_throtl_init(struct gendisk *disk)
* Freeze queue before activating policy, to synchronize with IO path,
* which is protected by 'q_usage_counter'.
*/
- blk_mq_freeze_queue(disk->queue);
+ memflags = blk_mq_freeze_queue(disk->queue);
blk_mq_quiesce_queue(disk->queue);
q->td = td;
@@ -1239,7 +1240,7 @@ static int blk_throtl_init(struct gendisk *disk)
out:
blk_mq_unquiesce_queue(disk->queue);
- blk_mq_unfreeze_queue(disk->queue);
+ blk_mq_unfreeze_queue(disk->queue, memflags);
return ret;
}