kernel/linux.git/block/blk.h, branch v5.10.258

blk-mq: use quiesced elevator switch when reinitializing queues

2026-06-01T15:29:15+00:00

[ Upstream commit 8237c01f1696bc53c470493bf1fe092a107648a6 ] The hctx's run_work may be racing with the elevator switch when reinitializing hardware queues. The queue is merely frozen in this context, but that only prevents requests from allocating and doesn't stop the hctx work from running. The work may get an elevator pointer that's being torn down, and can result in use-after-free errors and kernel panics (example below). Use the quiesced elevator switch instead, and make the previous one static since it is now only used locally. nvme nvme0: resetting controller nvme nvme0: 32/0/0 default/read/poll queues BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 80000020c8861067 P4D 80000020c8861067 PUD 250f8c8067 PMD 0 Oops: 0000 [#1] SMP PTI Workqueue: kblockd blk_mq_run_work_fn RIP: 0010:kyber_has_work+0x29/0x70 ... Call Trace: __blk_mq_do_dispatch_sched+0x83/0x2b0 __blk_mq_sched_dispatch_requests+0x12e/0x170 blk_mq_sched_dispatch_requests+0x30/0x60 __blk_mq_run_hw_queue+0x2b/0x50 process_one_work+0x1ef/0x380 worker_thread+0x2d/0x3e0 Signed-off-by: Keith Busch Reviewed-by: Ming Lei Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220927155652.3260724-1-kbusch@fb.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Brennan Lamoreaux Signed-off-by: Greg Kroah-Hartman

block: bump max plugged deferred size from 16 to 32

2021-11-18T13:03:57+00:00

[ Upstream commit ba0ffdd8ce48ad7f7e85191cd29f9674caca3745 ] Particularly for NVMe with efficient deferred submission for many requests, there are nice benefits to be seen by bumping the default max plug count from 16 to 32. This is especially true for virtualized setups, where the submit part is more expensive. But can be noticed even on native hardware. Reduce the multiple queue factor from 4 to 2, since we're changing the default size. While changing it, move the defines into the block layer private header. These aren't values that anyone outside of the block layer uses, or should use. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-throtl: optimize IOPS throttle for large IO scenarios

2021-09-15T07:50:25+00:00

[ Upstream commit 4f1e9630afe6332de7286820fedd019f19eac057 ] After patch 54efd50 (block: make generic_make_request handle arbitrarily sized bios), the IO through io-throttle may be larger, and these IOs may be further split into more small IOs. However, IOPS throttle does not seem to be aware of this change, which makes the calculation of IOPS of large IOs incomplete, resulting in disk-side IOPS that does not meet expectations. Maybe we should fix this problem. We can reproduce it by set max_sectors_kb of disk to 128, set blkio.write_iops_throttle to 100, run a dd instance inside blkio and use iostat to watch IOPS: dd if=/dev/zero of=/dev/sdb bs=1M count=1000 oflag=direct As a result, without this change the average IOPS is 1995, with this change the IOPS is 98. Signed-off-by: Chunguang Xu Acked-by: Tejun Heo Link: https://lore.kernel.org/r/65869aaad05475797d63b4c3fed4f529febe3c26.1627876014.git.brookxu@tencent.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-mq: fix is_flush_rq

2021-09-12T06:58:27+00:00

commit a9ed27a764156929efe714033edb3e9023c5f321 upstream. is_flush_rq() is called from bt_iter()/bt_tags_iter(), and runs the following check: hctx->fq->flush_rq == req but the passed hctx from bt_iter()/bt_tags_iter() may be NULL because: 1) memory re-order in blk_mq_rq_ctx_init(): rq->mq_hctx = data->hctx; ... refcount_set(&rq->ref, 1); OR 2) tag re-use and ->rqs[] isn't updated with new request. Fix the issue by re-writing is_flush_rq() as: return rq->end_io == flush_end_io; which turns out simpler to follow and immune to data race since we have ordered WRITE rq->end_io and refcount_set(&rq->ref, 1). Fixes: 2e315dc07df0 ("blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter") Cc: "Blank-Burian, Markus, Dr." Cc: Yufen Yu Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20210818010925.607383-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Cc: Yi Zhang Signed-off-by: Greg Kroah-Hartman

block: move blk_mq_sched_try_merge to blk-merge.c

2020-10-06T13:29:53+00:00

Move blk_mq_sched_try_merge to blk-merge.c, which allows to mark a lot of the merge infrastructure static there. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove the unused blk_integrity_merge_bio export

2020-10-06T13:29:53+00:00

Also move the definition from the public blkdev.h to the private block/blk.h header. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove the unused blk_integrity_merge_rq export

2020-10-06T13:29:53+00:00

Also move the definition from the public blkdev.h to the private block/blk.h header. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove the disk argument to delete_partition

2020-09-02T01:38:25+00:00

We can trivially derive the gendisk from the hd_struct. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: Add a new helper to attempt to merge a bio

2020-09-01T22:49:26+00:00

There are lots of duplicated code when trying to merge a bio from plug list and sw queue, we can introduce a new helper to attempt to merge a bio, which can simplify the blk_bio_list_merge() and blk_attempt_plug_merge(). Reviewed-by: Christoph Hellwig Signed-off-by: Baolin Wang Signed-off-by: Jens Axboe

block: Move blk_mq_bio_list_merge() into blk-merge.c

2020-09-01T22:49:26+00:00

Move the blk_mq_bio_list_merge() into blk-merge.c and rename it as a generic name. Reviewed-by: Christoph Hellwig Signed-off-by: Baolin Wang Signed-off-by: Jens Axboe