Re: [PATCH v6 3/4] block: implement runtime pm strategy

On 01/08/2013 01:21 AM, Alan Stern wrote:

On Sun, 6 Jan 2013, Aaron Lu wrote:

quoted

From: Lin Ming <redacted>

When a request is added:
    If device is suspended or is suspending and the request is not a
    PM request, resume the device.

When the last request finishes:
    Call pm_runtime_mark_last_busy() and pm_runtime_autosuspend().

When pick a request:
    If device is resuming/suspending, then only PM request is allowed to go.
    Return NULL for other cases.

[aaron.lu@intel.com: PM request does not involve nr_pending counting]
[aaron.lu@intel.com: No need to check q->dev]
[aaron.lu@intel.com: Autosuspend when the last request finished]
Signed-off-by: Lin Ming <redacted>
Signed-off-by: Aaron Lu <redacted>

quoted

--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h

@@ -974,6 +974,40 @@ extern int blk_pre_runtime_suspend(struct request_queue *q);
 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
 extern void blk_pre_runtime_resume(struct request_queue *q);
 extern void blk_post_runtime_resume(struct request_queue *q, int err);
+
+static inline void blk_pm_put_request(struct request *rq)
+{
+	if (!(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) {
+		pm_runtime_mark_last_busy(rq->q->dev);
+		pm_runtime_autosuspend(rq->q->dev);
+	}
+}
+
+static inline struct request *blk_pm_peek_request(
+	struct request_queue *q, struct request *rq)
+{
+	if (q->rpm_status == RPM_SUSPENDED ||
+		  (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))
+		return NULL;
+	else
+		return rq;
+}
+
+static inline void blk_pm_requeue_request(struct request *rq)
+{
+	if (!(rq->cmd_flags & REQ_PM))
+		rq->q->nr_pending--;
+}
+
+static inline void blk_pm_add_request(struct request_queue *q,
+	struct request *rq)
+{
+	if (!(rq->cmd_flags & REQ_PM) &&
+	    q->nr_pending++ == 0 &&
+	    (q->rpm_status == RPM_SUSPENDED ||
+	     q->rpm_status == RPM_SUSPENDING))
+		pm_request_resume(q->dev);
+}

These routines also don't belong in include/linux.  And they don't need 
to be marked inline.

OK, will move them.

What about create a new file blk-pm.c for all these block pm related
code?

Thanks,
Aaron