blk-mq: set RQF_USE_SCHED when the operation is known

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The cached requests are allocated for one operation but can be handed
out for another. A passthrough command has RQF_USE_SCHED cleared, so
using those flags for a subsequent read/write bio will insert it into
the scheduler without ->prepare_request() and frees it without
->finish_request(). For kyber, this leaks the domain token acquired at
dispatch and stalls the queue.

Don't set RQF_USE_SCHED based on the first operation the batch happened
to be allocated for. Instead, set it after the request is claimed by an
operation. Introduce a helper function, blk_mq_rq_late_init() for this,
and absorb blk_mq_rq_time_init() since the two run together.

Fixes: 4b6a5d9cea ("block: enable batched allocation for blk_mq_alloc_request()")
Link: https://lore.kernel.org/linux-block/20260916151655.2588-1-15815827059@163.com/
Reported-by: Henry Hu <huhai@kylinos.cn>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260922172711.1573186-1-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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This commit is contained in:

Keith Busch 2026-09-22 10:27:10 -07:00 • committed by Jens Axboe

parent 2a42e6fe12

commit ab6c756f28

2 changed files with 38 additions and 23 deletions

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59

block/blk-mq.c

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2

block/mq-deadline.c

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