From 46a243f72de931aad2632a0f3de3612534212ae9 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@neukum.org>
Date: Sun, 15 Jan 2012 00:16:51 +0100
Subject: [PATCH] [SCSI] st: implement PM
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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>
---
drivers/scsi/st.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 9b28f39bac26b..9262cdfa4b232 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];
--
2.39.5