diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2022-06-22 10:25:54 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-06-27 06:29:12 -0600 |
| commit | 3c8f9da41ed90294d8ca42b3ad8a13c5379bd549 (patch) | |
| tree | 0490614677bcd623cf875505e330b3089eb9582c /block | |
| parent | 1d87be8212c8c2bb1216a0ba49373e4e0123aaf3 (diff) | |
blk-mq: Don't disable preemption around __blk_mq_run_hw_queue().
__blk_mq_delay_run_hw_queue() disables preemption to get a stable
current CPU number and then invokes __blk_mq_run_hw_queue() if the CPU
number is part the mask.
__blk_mq_run_hw_queue() acquires a spin_lock_t which is a sleeping lock
on PREEMPT_RT and can't be acquired with disabled preemption.
It is not required for correctness to invoke __blk_mq_run_hw_queue() on
a CPU matching hctx->cpumask. Both (async and direct requests) can run
on a CPU not matching hctx->cpumask.
The CPU mask without disabling preemption and invoking
__blk_mq_run_hw_queue().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/YrLSEiNvagKJaDs5@linutronix.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index fa3dc4f8f35d..62b7025d6854 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2085,14 +2085,10 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, return; if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { - int cpu = get_cpu(); - if (cpumask_test_cpu(cpu, hctx->cpumask)) { + if (cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { __blk_mq_run_hw_queue(hctx); - put_cpu(); return; } - - put_cpu(); } kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, |