[SCSI] sd: implement START/STOP management

Implement SBC START/STOP management.  sdev->mange_start_stop is added.
When it's set to one, sd STOPs the device on suspend and shutdown and
STARTs it on resume.  sdev->manage_start_stop defaults is in sdev
instead of scsi_disk cdev to allow ->slave_config() override the
default configuration but is exported under scsi_disk sysfs node as
sdev->allow_restart is.

When manage_start_stop is zero (the default value), this patch doesn't
introduce any behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>

Rejections fixed and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 27 insertions, 4 deletions

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index c275dca..96db51c 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -278,6 +278,7 @@ static int scsi_bus_match(struct device *dev, struct device_driver *gendrv)
 
 static int scsi_bus_suspend(struct device * dev, pm_message_t state)
 {
+	struct device_driver *drv = dev->driver;
 	struct scsi_device *sdev = to_scsi_device(dev);
 	struct scsi_host_template *sht = sdev->host->hostt;
 	int err;
@@ -286,23 +287,45 @@ static int scsi_bus_suspend(struct device * dev, pm_message_t state)
 	if (err)
 		return err;
 
-	if (sht->suspend)
+	/* call HLD suspend first */
+	if (drv && drv->suspend) {
+		err = drv->suspend(dev, state);
+		if (err)
+			return err;
+	}
+
+	/* then, call host suspend */
+	if (sht->suspend) {
 		err = sht->suspend(sdev, state);
+		if (err) {
+			if (drv && drv->resume)
+				drv->resume(dev);
+			return err;
+		}
+	}
 
-	return err;
+	return 0;
 }
 
 static int scsi_bus_resume(struct device * dev)
 {
+	struct device_driver *drv = dev->driver;
 	struct scsi_device *sdev = to_scsi_device(dev);
 	struct scsi_host_template *sht = sdev->host->hostt;
-	int err = 0;
+	int err = 0, err2 = 0;
 
+	/* call host resume first */
 	if (sht->resume)
 		err = sht->resume(sdev);
 
+	/* then, call HLD resume */
+	if (drv && drv->resume)
+		err2 = drv->resume(dev);
+
 	scsi_device_resume(sdev);
-	return err;
+
+	/* favor LLD failure */
+	return err ? err : err2;;
 }
 
 struct bus_type scsi_bus_type = {