From 8f38f8e0a30e1c33cdfc48eba2bd63ac2eae373a Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Mon, 6 Jul 2020 11:14:36 -0400 Subject: 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 CC: Bart Van Assche Reviewed-by: Bart Van Assche Signed-off-by: Alan Stern Signed-off-by: Martin K. Petersen --- block/blk-pm.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-) (limited to 'block') diff --git a/block/blk-pm.c b/block/blk-pm.c index 1adc1cd748b4..b85234d758f7 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); -- cgit v1.2.3-58-ga151