[SCSI] st: implement PM

This implements basic power management for SCSI tapes.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 9b28f39bac26..9262cdfa4b23 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -1177,6 +1177,7 @@ static int check_tape(struct scsi_tape *STp, struct file *filp)
 static int st_open(struct inode *inode, struct file *filp)
 {
         int i, retval = (-EIO);
+        int resumed = 0;
         struct scsi_tape *STp;
         struct st_partstat *STps;
         int dev = TAPE_NR(inode);
@@ -1211,6 +1212,11 @@ static int st_open(struct inode *inode, struct file *filp)
         write_unlock(&st_dev_arr_lock);
         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
 
+        if (scsi_autopm_get_device(STp->device) < 0) {
+                retval = -EIO;
+                goto err_out;
+        }
+        resumed = 1;
         if (!scsi_block_when_processing_errors(STp->device)) {
                 retval = (-ENXIO);
                 goto err_out;
@@ -1258,6 +1264,8 @@ static int st_open(struct inode *inode, struct file *filp)
         normalize_buffer(STp->buffer);
         STp->in_use = 0;
         scsi_tape_put(STp);
+        if (resumed)
+                scsi_autopm_put_device(STp->device);
         mutex_unlock(&st_mutex);
         return retval;
 
@@ -1391,6 +1399,7 @@ static int st_release(struct inode *inode, struct file *filp)
         write_lock(&st_dev_arr_lock);
         STp->in_use = 0;
         write_unlock(&st_dev_arr_lock);
+        scsi_autopm_put_device(STp->device);
         scsi_tape_put(STp);
 
         return result;
@@ -4154,6 +4163,7 @@ static int st_probe(struct device *dev)
                 if (error)
                         goto out_free_tape;
         }
+        scsi_autopm_put_device(SDp);
 
         sdev_printk(KERN_NOTICE, SDp,
                     "Attached scsi tape %s\n", tape_name(tpnt));
@@ -4201,6 +4211,7 @@ static int st_remove(struct device *dev)
         struct scsi_tape *tpnt;
         int i, j, mode;
 
+        scsi_autopm_get_device(SDp);
         write_lock(&st_dev_arr_lock);
         for (i = 0; i < st_dev_max; i++) {
                 tpnt = scsi_tapes[i];