[SCSI] sr: support runtime pm
This patch adds runtime pm support for sr.
It did this by increasing the runtime usage_count of the device when
its block device is accessed. And decreasing the runtime usage_count
of the device when the access is done.
If there is media inside, runtime suspend is not allowed as we don't
always know if the ODD is being used or not.
The idea is discussed here:
http://thread.gmane.org/gmane.linux.acpi.devel/55243/focus=52703
and the restriction to check media inside is discussed here:
http://thread.gmane.org/gmane.linux.ide/53665/focus=58836
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 5fc97d2..2e8ddd7 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -45,6 +45,7 @@
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/slab.h>
+#include <linux/pm_runtime.h>
#include <asm/uaccess.h>
#include <scsi/scsi.h>
@@ -79,6 +80,11 @@
static int sr_probe(struct device *);
static int sr_remove(struct device *);
static int sr_done(struct scsi_cmnd *);
+static int sr_runtime_suspend(struct device *dev);
+
+static struct dev_pm_ops sr_pm_ops = {
+ .runtime_suspend = sr_runtime_suspend,
+};
static struct scsi_driver sr_template = {
.owner = THIS_MODULE,
@@ -86,6 +92,7 @@
.name = "sr",
.probe = sr_probe,
.remove = sr_remove,
+ .pm = &sr_pm_ops,
},
.done = sr_done,
};
@@ -131,6 +138,16 @@
return container_of(disk->private_data, struct scsi_cd, driver);
}
+static int sr_runtime_suspend(struct device *dev)
+{
+ struct scsi_cd *cd = dev_get_drvdata(dev);
+
+ if (cd->media_present)
+ return -EBUSY;
+ else
+ return 0;
+}
+
/*
* The get and put routines for the struct scsi_cd. Note this entity
* has a scsi_device pointer and owns a reference to this.
@@ -146,7 +163,8 @@
kref_get(&cd->kref);
if (scsi_device_get(cd->device))
goto out_put;
- goto out;
+ if (!scsi_autopm_get_device(cd->device))
+ goto out;
out_put:
kref_put(&cd->kref, sr_kref_release);
@@ -162,6 +180,7 @@
mutex_lock(&sr_ref_mutex);
kref_put(&cd->kref, sr_kref_release);
+ scsi_autopm_put_device(sdev);
scsi_device_put(sdev);
mutex_unlock(&sr_ref_mutex);
}
@@ -540,6 +559,8 @@
void __user *argp = (void __user *)arg;
int ret;
+ scsi_autopm_get_device(cd->device);
+
mutex_lock(&sr_mutex);
/*
@@ -571,6 +592,7 @@
out:
mutex_unlock(&sr_mutex);
+ scsi_autopm_put_device(cd->device);
return ret;
}
@@ -578,7 +600,13 @@
unsigned int clearing)
{
struct scsi_cd *cd = scsi_cd(disk);
- return cdrom_check_events(&cd->cdi, clearing);
+ unsigned int ret;
+
+ scsi_autopm_get_device(cd->device);
+ ret = cdrom_check_events(&cd->cdi, clearing);
+ scsi_autopm_put_device(cd->device);
+
+ return ret;
}
static int sr_block_revalidate_disk(struct gendisk *disk)
@@ -586,12 +614,16 @@
struct scsi_cd *cd = scsi_cd(disk);
struct scsi_sense_hdr sshdr;
+ scsi_autopm_get_device(cd->device);
+
/* if the unit is not ready, nothing more to do */
if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
- return 0;
+ goto out;
sr_cd_check(&cd->cdi);
get_sectorsize(cd);
+out:
+ scsi_autopm_put_device(cd->device);
return 0;
}
@@ -718,6 +750,8 @@
sdev_printk(KERN_DEBUG, sdev,
"Attached scsi CD-ROM %s\n", cd->cdi.name);
+ scsi_autopm_put_device(cd->device);
+
return 0;
fail_put:
@@ -965,6 +999,8 @@
{
struct scsi_cd *cd = dev_get_drvdata(dev);
+ scsi_autopm_get_device(cd->device);
+
blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn);
del_gendisk(cd->disk);