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Date: Mon, 6 Feb 2012 15:32:28 +0800
From: Huang Ying <ying.huang@...el.com>
To: Alan Stern <stern@...land.harvard.edu>
Cc: ming.m.lin@...el.com, linux-kernel@...r.kernel.org,
linux-scsi@...r.kernel.org, linux-pm@...r.kernel.org,
"Rafael J. Wysocki" <rjw@...k.pl>,
James Bottomley <JBottomley@...allels.com>,
Huang Ying <ying.huang@...el.com>
Subject: [RFC 5/5] scsi, sd, pm, request based runtime PM support
Can reduce power consumption when disk is mounted but no read/write
request.
TODO: Request based runtime PM may be harmful for rotating HD, should
enable that only for SSD and fallback to open/close based runtime PM
otherwise.
Signed-off-by: Huang Ying <ying.huang@...el.com>
---
drivers/scsi/scsi_lib.c | 3 ++-
drivers/scsi/scsi_priv.h | 1 +
drivers/scsi/sd.c | 43 +++++++++++++++++++++++++++++++++++++++++--
drivers/scsi/sd.h | 2 ++
4 files changed, 46 insertions(+), 3 deletions(-)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -401,7 +401,7 @@ static inline int scsi_host_is_busy(stru
* Notes: The previous command was completely finished, start
* a new one if possible.
*/
-static void scsi_run_queue(struct request_queue *q)
+void scsi_run_queue(struct request_queue *q)
{
struct scsi_device *sdev = q->queuedata;
struct Scsi_Host *shost;
@@ -454,6 +454,7 @@ static void scsi_run_queue(struct reques
blk_run_queue(q);
}
+EXPORT_SYMBOL_GPL(scsi_run_queue);
void scsi_requeue_run_queue(struct work_struct *work)
{
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -87,6 +87,7 @@ extern struct request_queue *scsi_alloc_
extern void scsi_free_queue(struct request_queue *q);
extern int scsi_init_queue(void);
extern void scsi_exit_queue(void);
+extern void scsi_run_queue(struct request_queue *q);
struct request_queue;
struct request;
extern struct kmem_cache *scsi_sdb_cache;
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -66,6 +66,7 @@
#include "sd.h"
#include "scsi_logging.h"
+#include "scsi_priv.h"
MODULE_AUTHOR("Eric Youngdale");
MODULE_DESCRIPTION("SCSI disk (sd) driver");
@@ -981,6 +982,8 @@ static int sd_open(struct block_device *
scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
}
+ scsi_autopm_put_device_sync(sdev);
+
return 0;
error_out:
@@ -1020,7 +1023,6 @@ static int sd_release(struct gendisk *di
* XXX is followed by a "rmmod sd_mod"?
*/
- scsi_autopm_put_device_sync(sdev);
scsi_disk_put(sdkp);
return 0;
}
@@ -1071,7 +1073,7 @@ static int sd_ioctl(struct block_device
struct scsi_device *sdp = sdkp->device;
void __user *p = (void __user *)arg;
int error;
-
+
SCSI_LOG_IOCTL(1, sd_printk(KERN_INFO, sdkp, "sd_ioctl: disk=%s, "
"cmd=0x%x\n", disk->disk_name, cmd));
@@ -1079,6 +1081,10 @@ static int sd_ioctl(struct block_device
if (error < 0)
return error;
+ error = scsi_autopm_get_device_sync(sdp);
+ if (error)
+ return error;
+
/*
* If we are in the middle of error recovery, don't let anyone
* else try and use this device. Also, if error recovery fails, it
@@ -1108,6 +1114,7 @@ static int sd_ioctl(struct block_device
break;
}
out:
+ scsi_autopm_put_device_sync(sdp);
return error;
}
@@ -2365,10 +2372,15 @@ static int sd_revalidate_disk(struct gen
struct scsi_device *sdp = sdkp->device;
unsigned char *buffer;
unsigned flush = 0;
+ int error;
SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
"sd_revalidate_disk\n"));
+ error = scsi_autopm_get_device_sync(sdp);
+ if (error)
+ return 0;
+
/*
* If the device is offline, don't try and read capacity or any
* of the other niceties.
@@ -2421,6 +2433,7 @@ static int sd_revalidate_disk(struct gen
kfree(buffer);
out:
+ scsi_autopm_put_device_sync(sdp);
return 0;
}
@@ -2490,6 +2503,29 @@ static int sd_format_disk_name(char *pre
return 0;
}
+static void sd_on_resume_work(struct work_struct *work)
+{
+ struct scsi_disk *sdkp = container_of(work, struct scsi_disk, work);
+ struct scsi_device *sdev = sdkp->device;
+
+ scsi_run_queue(sdev->request_queue);
+}
+
+/*
+ * Called with dev->power.lock held, scsi_run_queue will acquire the
+ * lock too, so delay to a work item to do that.
+ */
+static int sd_on_resume(struct notifier_block *nb, unsigned long event,
+ void *ptr)
+{
+ struct scsi_disk *sdkp = container_of(nb, struct scsi_disk, nb);
+
+ if (event == RPM_REQ_RESUME)
+ schedule_work(&sdkp->work);
+
+ return NOTIFY_DONE;
+}
+
/*
* The asynchronous part of sd_probe
*/
@@ -2543,6 +2579,9 @@ static void sd_probe_async(void *data, a
sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
sdp->removable ? "removable " : "");
+ INIT_WORK(&sdkp->work, sd_on_resume_work);
+ sdkp->nb.notifier_call = sd_on_resume;
+ atomic_notifier_chain_register(&dev->power.notifier, &sdkp->nb);
scsi_autopm_put_device_sync(sdp);
put_device(&sdkp->dev);
}
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -50,6 +50,8 @@ struct scsi_disk {
struct scsi_driver *driver; /* always &sd_template */
struct scsi_device *device;
struct device dev;
+ struct notifier_block nb;
+ struct work_struct work;
struct gendisk *disk;
atomic_t openers;
sector_t capacity; /* size in 512-byte sectors */
--
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