[SCSI] sr: use block layer runtime PM

Migrate sr to make use of block layer runtime PM. Accordingly, the
SCSI bus layer runtime PM callback is simplified as all SCSI drivers
implementing runtime PM now use the block layer's request-based
mechanism.

Note that due to the device will be polled by kernel at a constant
interval, if the autosuspend delay is set longer than the polling
interval then the device will never suspend.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/scsi_pm.c

@@ -16,6 +16,8 @@
 
 #include "scsi_priv.h"
 
+#ifdef CONFIG_PM_SLEEP
+
 static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device *))
 {
 	int err;
@@ -43,8 +45,6 @@ static int scsi_dev_type_resume(struct device *dev, int (*cb)(struct device *))
 	return err;
 }
 
-#ifdef CONFIG_PM_SLEEP
-
 static int
 scsi_bus_suspend_common(struct device *dev, int (*cb)(struct device *))
 {
@@ -145,38 +145,22 @@ static int scsi_bus_restore(struct device *dev)
 
 #ifdef CONFIG_PM_RUNTIME
 
-static int sdev_blk_runtime_suspend(struct scsi_device *sdev,
-					int (*cb)(struct device *))
+static int sdev_runtime_suspend(struct device *dev)
 {
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	struct scsi_device *sdev = to_scsi_device(dev);
 	int err;
 
 	err = blk_pre_runtime_suspend(sdev->request_queue);
 	if (err)
 		return err;
-	if (cb)
-		err = cb(&sdev->sdev_gendev);
+	if (pm && pm->runtime_suspend)
+		err = pm->runtime_suspend(dev);
 	blk_post_runtime_suspend(sdev->request_queue, err);
 
 	return err;
 }
 
-static int sdev_runtime_suspend(struct device *dev)
-{
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-	int (*cb)(struct device *) = pm ? pm->runtime_suspend : NULL;
-	struct scsi_device *sdev = to_scsi_device(dev);
-	int err;
-
-	if (sdev->request_queue->dev)
-		return sdev_blk_runtime_suspend(sdev, cb);
-
-	err = scsi_dev_type_suspend(dev, cb);
-	if (err == -EAGAIN)
-		pm_schedule_suspend(dev, jiffies_to_msecs(
-					round_jiffies_up_relative(HZ/10)));
-	return err;
-}
-
 static int scsi_runtime_suspend(struct device *dev)
 {
 	int err = 0;
@@ -190,31 +174,20 @@ static int scsi_runtime_suspend(struct device *dev)
 	return err;
 }
 
-static int sdev_blk_runtime_resume(struct scsi_device *sdev,
-					int (*cb)(struct device *))
+static int sdev_runtime_resume(struct device *dev)
 {
+	struct scsi_device *sdev = to_scsi_device(dev);
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
 	int err = 0;
 
 	blk_pre_runtime_resume(sdev->request_queue);
-	if (cb)
-		err = cb(&sdev->sdev_gendev);
+	if (pm && pm->runtime_resume)
+		err = pm->runtime_resume(dev);
 	blk_post_runtime_resume(sdev->request_queue, err);
 
 	return err;
 }
 
-static int sdev_runtime_resume(struct device *dev)
-{
-	struct scsi_device *sdev = to_scsi_device(dev);
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-	int (*cb)(struct device *) = pm ? pm->runtime_resume : NULL;
-
-	if (sdev->request_queue->dev)
-		return sdev_blk_runtime_resume(sdev, cb);
-	else
-		return scsi_dev_type_resume(dev, cb);
-}
-
 static int scsi_runtime_resume(struct device *dev)
 {
 	int err = 0;
@@ -235,14 +208,11 @@ static int scsi_runtime_idle(struct device *dev)
 	/* Insert hooks here for targets, hosts, and transport classes */
 
 	if (scsi_is_sdev_device(dev)) {
-		struct scsi_device *sdev = to_scsi_device(dev);
-
-		if (sdev->request_queue->dev) {
 		pm_runtime_mark_last_busy(dev);
 		pm_runtime_autosuspend(dev);
 		return -EBUSY;
 	}
-	}
+
 	return 0;
 }
 

drivers/scsi/sr.c

@@ -161,14 +161,10 @@ static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
 		goto out;
 	cd = scsi_cd(disk);
 	kref_get(&cd->kref);
-	if (scsi_device_get(cd->device))
-		goto out_put;
-	if (!scsi_autopm_get_device(cd->device))
-		goto out;
-
- out_put:
+	if (scsi_device_get(cd->device)) {
 		kref_put(&cd->kref, sr_kref_release);
 		cd = NULL;
+	}
  out:
 	mutex_unlock(&sr_ref_mutex);
 	return cd;
@@ -180,7 +176,6 @@ static void scsi_cd_put(struct scsi_cd *cd)
 
 	mutex_lock(&sr_ref_mutex);
 	kref_put(&cd->kref, sr_kref_release);
-	scsi_autopm_put_device(sdev);
 	scsi_device_put(sdev);
 	mutex_unlock(&sr_ref_mutex);
 }
@@ -558,8 +553,6 @@ static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 	void __user *argp = (void __user *)arg;
 	int ret;
 
-	scsi_autopm_get_device(cd->device);
-
 	mutex_lock(&sr_mutex);
 
 	/*
@@ -591,7 +584,6 @@ static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 
 out:
 	mutex_unlock(&sr_mutex);
-	scsi_autopm_put_device(cd->device);
 	return ret;
 }
 
@@ -599,17 +591,11 @@ static unsigned int sr_block_check_events(struct gendisk *disk,
 					  unsigned int clearing)
 {
 	struct scsi_cd *cd = scsi_cd(disk);
-	unsigned int ret;
 
-	if (atomic_read(&cd->device->disk_events_disable_depth) == 0) {
-		scsi_autopm_get_device(cd->device);
-		ret = cdrom_check_events(&cd->cdi, clearing);
-		scsi_autopm_put_device(cd->device);
-	} else {
-		ret = 0;
-	}
+	if (atomic_read(&cd->device->disk_events_disable_depth))
+		return 0;
 
-	return ret;
+	return cdrom_check_events(&cd->cdi, clearing);
 }
 
 static int sr_block_revalidate_disk(struct gendisk *disk)
@@ -617,8 +603,6 @@ static int sr_block_revalidate_disk(struct gendisk *disk)
 	struct scsi_cd *cd = scsi_cd(disk);
 	struct scsi_sense_hdr sshdr;
 
-	scsi_autopm_get_device(cd->device);
-
 	/* if the unit is not ready, nothing more to do */
 	if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
 		goto out;
@@ -626,7 +610,6 @@ static int sr_block_revalidate_disk(struct gendisk *disk)
 	sr_cd_check(&cd->cdi);
 	get_sectorsize(cd);
 out:
-	scsi_autopm_put_device(cd->device);
 	return 0;
 }
 
@@ -747,6 +730,12 @@ static int sr_probe(struct device *dev)
 	if (register_cdrom(&cd->cdi))
 		goto fail_put;
 
+	/*
+	 * Initialize block layer runtime PM stuffs before the
+	 * periodic event checking request gets started in add_disk.
+	 */
+	blk_pm_runtime_init(sdev->request_queue, dev);
+
 	dev_set_drvdata(dev, cd);
 	disk->flags |= GENHD_FL_REMOVABLE;
 	add_disk(disk);