scsi: block: pm: Simplify resume handling
Commit 05d18ae1cc8a ("scsi: pm: Balance pm_only counter of request queue
during system resume") fixed a problem in the block layer's runtime-PM
code: blk_set_runtime_active() failed to call blk_clear_pm_only().
However, the commit's implementation was awkward; it forced the SCSI
system-resume handler to choose whether to call blk_post_runtime_resume()
or blk_set_runtime_active(), depending on whether or not the SCSI device
had previously been runtime suspended.
This patch simplifies the situation considerably by adding the missing
function call directly into blk_set_runtime_active() (under the condition
that the queue is not already in the RPM_ACTIVE state). This allows the
SCSI routine to revert back to its original form. Furthermore, making this
change reveals that blk_post_runtime_resume() (in its success pathway) does
exactly the same thing as blk_set_runtime_active(). The duplicate code is
easily removed by making one routine call the other.
No functional changes are intended.
Link: https://lore.kernel.org/r/20200706151436.GA702867@rowland.harvard.edu
CC: Can Guo <cang@codeaurora.org>
CC: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/block/blk-pm.c b/block/blk-pm.c
index 1adc1cd..b85234d 100644
--- a/block/blk-pm.c
+++ b/block/blk-pm.c
@@ -164,9 +164,8 @@ EXPORT_SYMBOL(blk_pre_runtime_resume);
*
* Description:
* Update the queue's runtime status according to the return value of the
- * device's runtime_resume function. If it is successfully resumed, process
- * the requests that are queued into the device's queue when it is resuming
- * and then mark last busy and initiate autosuspend for it.
+ * device's runtime_resume function. If the resume was successful, call
+ * blk_set_runtime_active() to do the real work of restarting the queue.
*
* This function should be called near the end of the device's
* runtime_resume callback.
@@ -175,19 +174,13 @@ void blk_post_runtime_resume(struct request_queue *q, int err)
{
if (!q->dev)
return;
-
- spin_lock_irq(&q->queue_lock);
if (!err) {
- q->rpm_status = RPM_ACTIVE;
- pm_runtime_mark_last_busy(q->dev);
- pm_request_autosuspend(q->dev);
+ blk_set_runtime_active(q);
} else {
+ spin_lock_irq(&q->queue_lock);
q->rpm_status = RPM_SUSPENDED;
+ spin_unlock_irq(&q->queue_lock);
}
- spin_unlock_irq(&q->queue_lock);
-
- if (!err)
- blk_clear_pm_only(q);
}
EXPORT_SYMBOL(blk_post_runtime_resume);
@@ -204,15 +197,25 @@ EXPORT_SYMBOL(blk_post_runtime_resume);
* This function can be used in driver's resume hook to correct queue
* runtime PM status and re-enable peeking requests from the queue. It
* should be called before first request is added to the queue.
+ *
+ * This function is also called by blk_post_runtime_resume() for successful
+ * runtime resumes. It does everything necessary to restart the queue.
*/
void blk_set_runtime_active(struct request_queue *q)
{
- if (q->dev) {
- spin_lock_irq(&q->queue_lock);
- q->rpm_status = RPM_ACTIVE;
- pm_runtime_mark_last_busy(q->dev);
- pm_request_autosuspend(q->dev);
- spin_unlock_irq(&q->queue_lock);
- }
+ int old_status;
+
+ if (!q->dev)
+ return;
+
+ spin_lock_irq(&q->queue_lock);
+ old_status = q->rpm_status;
+ q->rpm_status = RPM_ACTIVE;
+ pm_runtime_mark_last_busy(q->dev);
+ pm_request_autosuspend(q->dev);
+ spin_unlock_irq(&q->queue_lock);
+
+ if (old_status != RPM_ACTIVE)
+ blk_clear_pm_only(q);
}
EXPORT_SYMBOL(blk_set_runtime_active);