From: Zhao Wuyun <zhaowuyun.zwy@xxxxxxxxxxxxxxx>
queue blocked during runtime PM when at the following situation:
process A:
runtime suspend run and set the PM status to RPM_SUSPENDING
then run req with RQF_PM with blk_execute_rq(req->q, NULL, req, 1)
then the req queued to head
it is not executed when the driver is busy
process B:
normal device management operation
run req with no RQF_PM with blk_execute_rq(req->q, NULL, req, 1)
the the req is queued in front of the RQF_PM req of process A
__blk_run_queue still not run
because the first req is non RQF_PM req and with RQF_SOFTBARRIER,
so the queue is totally blocked when at RPM_SUSPENDING status.
see the following task calltrace:
process A:
[<ffffff9d87e86150>] __switch_to+0x10c
[<ffffff9d88ed8ab0>] __schedule+0x670
[<ffffff9d88ed8d18>] schedule+0x74
[<ffffff9d88edc8f4>] schedule_timeout+0x328
[<ffffff9d88ed9130>] io_schedule_timeout+0x24
[<ffffff9d88ed9b10>] wait_for_common_io+0x90
[<ffffff9d88ed9bb4>] wait_for_completion_io_timeout+0x24
[<ffffff9d8829e1e0>] blk_execute_rq+0x88
[<ffffff9d8859b3a4>] scsi_execute+0x114
[<ffffff9d885c4070>] sd_sync_cache+0xfc
[<ffffff9d885c439c>] sd_suspend_common+0x58
[<ffffff9d885c4338>] sd_suspend_runtime+0x20
[<ffffff9d885a73cc>] scsi_runtime_suspend+0x70
[<ffffff9d885341e8>] __rpm_callback+0xcc
[<ffffff9d885340e8>] rpm_callback+0x5c
[<ffffff9d88532134>] rpm_suspend+0x1e8
[<ffffff9d88533b28>] pm_runtime_work+0x7c
[<ffffff9d87ed31d4>] process_one_work+0x1bc
[<ffffff9d87ed3668>] worker_thread+0x214
[<ffffff9d87ed839c>] kthread+0x11c
[<ffffff9d87e84fcc>] ret_from_fork+0x10
process B:
[<ffffff9d87e86150>] __switch_to+0x10c
[<ffffff9d88ed8ab0>] __schedule+0x670
[<ffffff9d88ed8d18>] schedule+0x74
[<ffffff9d88edc8f4>] schedule_timeout+0x328
[<ffffff9d88ed9130>] io_schedule_timeout+0x24
[<ffffff9d88ed9b10>] wait_for_common_io+0x90
[<ffffff9d88ed9bb4>] wait_for_completion_io_timeout+0x24
[<ffffff9d8829e1e0>] blk_execute_rq+0x88
[<ffffff9d8859b3a4>] scsi_execute+0x114
[<ffffff9d8859d854>] scsi_test_unit_ready+0x70
[<ffffff9d885c2f48>] sd_check_events+0xd4
[<ffffff9d882abde8>] disk_check_events+0x58
[<ffffff9d882acc0c>] disk_events_workfn+0x20
[<ffffff9d87ed31d4>] process_one_work+0x1bc
[<ffffff9d87ed3668>] worker_thread+0x214
[<ffffff9d87ed839c>] kthread+0x11c
[<ffffff9d87e84fcc>] ret_from_fork+0x10
Signed-off-by: Zhao Wuyun <zhaowuyun.zwy@xxxxxxxxxxxxxxx>
---
block/blk-core.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index a33775cd97be..8b9272bfdc09 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2856,6 +2856,15 @@ static struct request *elv_next_request(struct request_queue *q)
if (blk_pm_allow_request(rq))
return rq;
+ /*
+ * let the PM request run,
+ * or the queue may be blocked by the non-PM request
+ * with RQF_SOFTBARRIER forever while doing runtime PM.
+ */
+ if (q->rpm_status == RPM_SUSPENDING
+ || q->rpm_status == RPM_RESUMING)
+ continue;
+
if (rq->rq_flags & RQF_SOFTBARRIER)
break;
}
--
2.32.1 (Apple Git-133)
