[SCSI] sd: add support for runtime PM

This patch (as1399) adds runtime-PM support to the sd driver.  The
support is unsophisticated: If a SCSI disk device is mounted, or if
its device file is held open, then the device will not be
runtime-suspended; otherwise it will (provided userspace gives
permission by writing "auto" to the sysfs power/control attribute).

In order to make this work, a dev_set_drvdata() call had to be moved
from sd_probe_async() to sd_probe().  Also, a few lines of code were
changed to use a local variable instead of recalculating the address
of an embedded struct device.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 16 insertions, 5 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 8802e48bc063..cc8a1d1d915a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -759,6 +759,10 @@ static int sd_open(struct block_device *bdev, fmode_t mode)
 
         sdev = sdkp->device;
 
+        retval = scsi_autopm_get_device(sdev);
+        if (retval)
+                goto error_autopm;
+
         /*
          * If the device is in error recovery, wait until it is done.
          * If the device is offline, then disallow any access to it.
@@ -803,6 +807,8 @@ static int sd_open(struct block_device *bdev, fmode_t mode)
         return 0;
 
 error_out:
+        scsi_autopm_put_device(sdev);
+error_autopm:
         scsi_disk_put(sdkp);
         return retval;  
 }
@@ -834,6 +840,8 @@ static int sd_release(struct gendisk *disk, fmode_t mode)
          * XXX and what if there are packets in flight and this close()
          * XXX is followed by a "rmmod sd_mod"?
          */
+
+        scsi_autopm_put_device(sdev);
         scsi_disk_put(sdkp);
         return 0;
 }
@@ -2232,7 +2240,6 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
         if (sdp->removable)
                 gd->flags |= GENHD_FL_REMOVABLE;
 
-        dev_set_drvdata(dev, sdkp);
         add_disk(gd);
         sd_dif_config_host(sdkp);
 
@@ -2240,6 +2247,7 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 
         sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
                   sdp->removable ? "removable " : "");
+        scsi_autopm_put_device(sdp);
         put_device(&sdkp->dev);
 }
 
@@ -2317,14 +2325,15 @@ static int sd_probe(struct device *dev)
         }
 
         device_initialize(&sdkp->dev);
-        sdkp->dev.parent = &sdp->sdev_gendev;
+        sdkp->dev.parent = dev;
         sdkp->dev.class = &sd_disk_class;
-        dev_set_name(&sdkp->dev, dev_name(&sdp->sdev_gendev));
+        dev_set_name(&sdkp->dev, dev_name(dev));
 
         if (device_add(&sdkp->dev))
                 goto out_free_index;
 
-        get_device(&sdp->sdev_gendev);
+        get_device(dev);
+        dev_set_drvdata(dev, sdkp);
 
         get_device(&sdkp->dev); /* prevent release before async_schedule */
         async_schedule(sd_probe_async, sdkp);
@@ -2358,8 +2367,10 @@ static int sd_remove(struct device *dev)
 {
         struct scsi_disk *sdkp;
 
-        async_synchronize_full();
         sdkp = dev_get_drvdata(dev);
+        scsi_autopm_get_device(sdkp->device);
+
+        async_synchronize_full();
         blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn);
         device_del(&sdkp->dev);
         del_gendisk(sdkp->disk);