[v14,1/3] scsi: sr: support runtime pm

Commit Message

Aaron Lu Jan. 23, 2013, 7:09 a.m. UTC

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 <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Acked-by: James Bottomley <[e-mail]>
---
 drivers/scsi/sr.c | 42 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

Comments

Jeff Garzik Jan. 25, 2013, 8:37 p.m. UTC | #1

On 01/23/2013 02:09 AM, Aaron Lu wrote:
> 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 <[e-mail]>
> Acked-by: Alan Stern <[e-mail]>
> Acked-by: James Bottomley <[e-mail]>
> ---
>   drivers/scsi/sr.c | 42 +++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 39 insertions(+), 3 deletions(-)

applied 1-3



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Aaron Lu Jan. 28, 2013, 1:36 a.m. UTC | #2

On Fri, Jan 25, 2013 at 03:37:28PM -0500, Jeff Garzik wrote:
> On 01/23/2013 02:09 AM, Aaron Lu wrote:
> >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 <[e-mail]>
> >Acked-by: Alan Stern <[e-mail]>
> >Acked-by: James Bottomley <[e-mail]>
> >---
> >  drivers/scsi/sr.c | 42 +++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 39 insertions(+), 3 deletions(-)
> 
> applied 1-3

Now that the whole patchset is queued, I would like to thank all of you,
especially Alan Stern and Tejun Heo, for your kind help, without that I
would not be able to make it.

Thanks and best regards,
Aaron

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Tejun Heo Jan. 28, 2013, 7:14 p.m. UTC | #3

Hey, Aaron.

Thank *you* for the persistence.  It was a pleasure to work with you. :)

Patch

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 DEFINE_MUTEX(sr_mutex);
 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 @@  static struct scsi_driver sr_template = {
 		.name   	= "sr",
 		.probe		= sr_probe,
 		.remove		= sr_remove,
+		.pm		= &sr_pm_ops,
 	},
 	.done			= sr_done,
 };
@@ -131,6 +138,16 @@  static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
 	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 @@  static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
 	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 @@  static void scsi_cd_put(struct scsi_cd *cd)
 
 	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 @@  static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 	void __user *argp = (void __user *)arg;
 	int ret;
 
+	scsi_autopm_get_device(cd->device);
+
 	mutex_lock(&sr_mutex);
 
 	/*
@@ -571,6 +592,7 @@  static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 
 out:
 	mutex_unlock(&sr_mutex);
+	scsi_autopm_put_device(cd->device);
 	return ret;
 }
 
@@ -578,7 +600,13 @@  static unsigned int sr_block_check_events(struct gendisk *disk,
 					  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 @@  static int sr_block_revalidate_disk(struct gendisk *disk)
 	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 @@  static int sr_probe(struct device *dev)
 
 	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 @@  static int sr_remove(struct device *dev)
 {
 	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);