[PATCH 2/4] scsi: avoid to quiesce sdev->request_queue two times
From: Ming Lei <hidden>
Date: 2021-11-03 03:44:16
Also in:
linux-nvme, linux-scsi
Subsystem:
scsi subsystem, the rest · Maintainers:
"James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
For fixing queue quiesce race between driver and block layer(elevator
switch, update nr_requests, ...), we need to support concurrent quiesce
and unquiesce, which requires the two to be balanced.
blk_mq_quiesce_queue() calls blk_mq_quiesce_queue_nowait() for updating
quiesce depth and marking the flag, then scsi_internal_device_block() calls
blk_mq_quiesce_queue_nowait() two times actually.
Fix the double quiesce and keep quiesce and unquiesce balanced.
Reported-by: Yi Zhang <redacted>
Fixes: e70feb8b3e68 ("blk-mq: support concurrent queue quiesce/unquiesce")
Signed-off-by: Ming Lei <redacted>
---
drivers/scsi/scsi_lib.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9c2b99e12ce3..1cd3ef9056d5 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c@@ -2645,6 +2645,14 @@ scsi_target_resume(struct scsi_target *starget) } EXPORT_SYMBOL(scsi_target_resume); +static int __scsi_internal_device_block_nowait(struct scsi_device *sdev) +{ + if (scsi_device_set_state(sdev, SDEV_BLOCK)) + return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); + + return 0; +} + /** * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state * @sdev: device to block
@@ -2661,24 +2669,16 @@ EXPORT_SYMBOL(scsi_target_resume); */ int scsi_internal_device_block_nowait(struct scsi_device *sdev) { - struct request_queue *q = sdev->request_queue; - int err = 0; - - err = scsi_device_set_state(sdev, SDEV_BLOCK); - if (err) { - err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); - - if (err) - return err; - } + int ret = __scsi_internal_device_block_nowait(sdev); /* * The device has transitioned to SDEV_BLOCK. Stop the * block layer from calling the midlayer with this device's * request queue. */ - blk_mq_quiesce_queue_nowait(q); - return 0; + if (!ret) + blk_mq_quiesce_queue_nowait(sdev->request_queue); + return ret; } EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
@@ -2699,13 +2699,12 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); */ static int scsi_internal_device_block(struct scsi_device *sdev) { - struct request_queue *q = sdev->request_queue; int err; mutex_lock(&sdev->state_mutex); - err = scsi_internal_device_block_nowait(sdev); + err = __scsi_internal_device_block_nowait(sdev); if (err == 0) - blk_mq_quiesce_queue(q); + blk_mq_quiesce_queue(sdev->request_queue); mutex_unlock(&sdev->state_mutex); return err;
--
2.31.1