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blk-mq: Abort suspend when wakeup events are pending 

During system suspend, wakeup capable IRQs for block device can be
delayed, which can cause blk_mq_hctx_notify_offline() to hang
indefinitely while waiting for pending request to complete.
Skip the request waiting loop and abort suspend when wakeup events are
pending to prevent the deadlock.

Fixes: bf0beec060 ("blk-mq: drain I/O when all CPUs in a hctx are offline")
Signed-off-by: Cong Zhang <cong.zhang@oss.qualcomm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
pull/1354/merge
Cong Zhang 2025-12-03 11:34:21 +08:00 committed by Jens Axboe
parent 71075d25ca
commit c196bf43d7
1 changed files with 16 additions and 2 deletions
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18
block/blk-mq.c
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@ -23,6 +23,7 @@
#include <linux/cache.h>
#include <linux/sched/topology.h>
#include <linux/sched/signal.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/crash_dump.h>
#include <linux/prefetch.h>
@ -3718,6 +3719,7 @@ static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
{
struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
struct blk_mq_hw_ctx, cpuhp_online);
int ret = 0;
if (blk_mq_hctx_has_online_cpu(hctx, cpu))
return 0;
@ -3738,12 +3740,24 @@ static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
* frozen and there are no requests.
*/
if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
while (blk_mq_hctx_has_requests(hctx))
while (blk_mq_hctx_has_requests(hctx)) {
/*
* The wakeup capable IRQ handler of block device is
* not called during suspend. Skip the loop by checking
* pm_wakeup_pending to prevent the deadlock and improve
* suspend latency.
*/
if (pm_wakeup_pending()) {
clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
ret = -EBUSY;
break;
}
msleep(5);
}
percpu_ref_put(&hctx->queue->q_usage_counter);
}
return 0;
return ret;
}
/*