6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Cong Zhang cong.zhang@oss.qualcomm.com
[ Upstream commit c196bf43d706592d8801a7513603765080e495fb ]
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: bf0beec0607d ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 373a67a630f3b..d3ced0cff9161 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -24,6 +24,7 @@ #include <linux/sched/sysctl.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> @@ -3510,6 +3511,7 @@ 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 (!cpumask_test_cpu(cpu, hctx->cpumask) || !blk_mq_last_cpu_in_hctx(cpu, hctx)) @@ -3531,12 +3533,24 @@ 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; }
static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)