[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>

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 9b28f39..9262cdf 100644 (file)
--- 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];