kernel/linux.git/block/blk-mq.h, branch linux-7.1.y

blk-mq: use queue_hctx in blk_mq_map_queue_type

2025-12-01T14:18:31+00:00

Some caller of blk_mq_map_queue_type now didn't grab 'q_usage_counter', such as blk_mq_cpu_mapped_to_hctx, so we need protect 'queue_hw_ctx' through rcu. Also checked all other functions, no more missed cases. Fixes: 89e1fb7ceffd ("blk-mq: fix potential uaf for 'queue_hw_ctx'") Reported-by: Jens Axboe Signed-off-by: Fengnan Chang Signed-off-by: Jens Axboe

blk-mq: use array manage hctx map instead of xarray

2025-11-28T16:09:19+00:00

After commit 4e5cc99e1e48 ("blk-mq: manage hctx map via xarray"), we use an xarray instead of array to store hctx, but in poll mode, each time in blk_mq_poll, we need use xa_load to find corresponding hctx, this introduce some costs. In my test, xa_load may cost 3.8% cpu. This patch revert previous change, eliminates the overhead of xa_load and can result in a 3% performance improvement. Signed-off-by: Fengnan Chang Signed-off-by: Jens Axboe

blk-mq: fix stale tag depth for shared sched tags in blk_mq_update_nr_requests()

2025-10-15T13:49:19+00:00

Commit 7f2799c546db ("blk-mq: cleanup shared tags case in blk_mq_update_nr_requests()") moves blk_mq_tag_update_sched_shared_tags() before q->nr_requests is updated, however, it's still using the old q->nr_requests to resize tag depth. Fix this problem by passing in expected new tag depth. Fixes: 7f2799c546db ("blk-mq: cleanup shared tags case in blk_mq_update_nr_requests()") Signed-off-by: Yu Kuai Reviewed-by: Ming Lei Reviewed-by: Nilay Shroff Reported-by: Chris Mason Link: https://lore.kernel.org/linux-block/20251014130507.4187235-2-clm@meta.com/ Signed-off-by: Jens Axboe

blk-mq: remove blk_mq_tag_update_depth()

2025-09-10T11:25:56+00:00

This helper is not used now. Signed-off-by: Yu Kuai Reviewed-by: Nilay Shroff Signed-off-by: Jens Axboe

blk-mq: fix potential deadlock while nr_requests grown

2025-09-10T11:25:56+00:00

Allocate and free sched_tags while queue is freezed can deadlock[1], this is a long term problem, hence allocate memory before freezing queue and free memory after queue is unfreezed. [1] https://lore.kernel.org/all/0659ea8d-a463-47c8-9180-43c719e106eb@linux.ibm.com/ Fixes: e3a2b3f931f5 ("blk-mq: allow changing of queue depth through sysfs") Signed-off-by: Yu Kuai Reviewed-by: Nilay Shroff Signed-off-by: Jens Axboe

blk-mq-sched: add new parameter nr_requests in blk_mq_alloc_sched_tags()

2025-09-10T11:25:56+00:00

This helper only support to allocate the default number of requests, add a new parameter to support specific number of requests. Prepare to fix potential deadlock in the case nr_requests grow. Signed-off-by: Yu Kuai Reviewed-by: Nilay Shroff Signed-off-by: Jens Axboe

blk-mq: check invalid nr_requests in queue_requests_store()

2025-09-10T11:25:56+00:00

queue_requests_store() is the only caller of blk_mq_update_nr_requests(), and blk_mq_update_nr_requests() is the only caller of blk_mq_tag_update_depth(), however, they all have checkings for nr_requests input by user. Make code cleaner by moving all the checkings to the top function: 1) nr_requests > reserved tags; 2) if there is elevator, 4 <= nr_requests <= 2048; 3) if elevator is none, 4 <= nr_requests <= tag_set->queue_depth; Meanwhile, case 2 is the only case tags can grow and -ENOMEM might be returned. Signed-off-by: Yu Kuai Reviewed-by: Nilay Shroff Signed-off-by: Jens Axboe

blk-mq: Pass tag_set to blk_mq_free_rq_map/tags

2025-09-08T14:05:32+00:00

To prepare for converting the tag->rqs freeing to be SRCU-based, the tag_set is needed in the freeing helper functions. This patch adds 'struct blk_mq_tag_set *' as the first parameter to blk_mq_free_rq_map() and blk_mq_free_tags(), and updates all their call sites. This allows access to the tag_set's SRCU structure in the next step, which will be used to free the tag maps after a grace period. No functional change is intended in this patch. Reviewed-by: Hannes Reinecke Reviewed-by: Yu Kuai Signed-off-by: Ming Lei Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe

block: clean up blk_mq_in_flight_rw()

2025-05-10T08:11:21+00:00

Also add comment for part_inflight_show() for the difference between bio-based and rq-based device. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-4-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig

blk-mq: remove blk_mq_in_flight()

2025-05-10T08:04:38+00:00

After commit 7be835694dae ("block: fix that util can be greater than 100%"), it's not used and can be removed. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-1-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Reviewed-by: John Garry Reviewed-by: Hannes Reinecke