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[SCSI] sd: implement START/STOP management
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Implement SBC START/STOP management.  sdev->mange_start_stop is added.
When it's set to one, sd STOPs the device on suspend and shutdown and
STARTs it on resume.  sdev->manage_start_stop defaults is in sdev
instead of scsi_disk cdev to allow ->slave_config() override the
default configuration but is exported under scsi_disk sysfs node as
sdev->allow_restart is.

When manage_start_stop is zero (the default value), this patch doesn't
introduce any behavior change.

Signed-off-by: Tejun Heo <[email protected]>

Rejections fixed and
Signed-off-by: James Bottomley <[email protected]>
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@htejun
htejun authored and James Bottomley committed Mar 20, 2007
1 parent 3721050 commit c3c94c5
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Showing 4 changed files with 131 additions and 4 deletions.
31 changes: 27 additions & 4 deletions drivers/scsi/scsi_sysfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -278,6 +278,7 @@ static int scsi_bus_match(struct device *dev, struct device_driver *gendrv)

static int scsi_bus_suspend(struct device * dev, pm_message_t state)
{
struct device_driver *drv = dev->driver;
struct scsi_device *sdev = to_scsi_device(dev);
struct scsi_host_template *sht = sdev->host->hostt;
int err;
Expand All @@ -286,23 +287,45 @@ static int scsi_bus_suspend(struct device * dev, pm_message_t state)
if (err)
return err;

if (sht->suspend)
/* call HLD suspend first */
if (drv && drv->suspend) {
err = drv->suspend(dev, state);
if (err)
return err;
}

/* then, call host suspend */
if (sht->suspend) {
err = sht->suspend(sdev, state);
if (err) {
if (drv && drv->resume)
drv->resume(dev);
return err;
}
}

return err;
return 0;
}

static int scsi_bus_resume(struct device * dev)
{
struct device_driver *drv = dev->driver;
struct scsi_device *sdev = to_scsi_device(dev);
struct scsi_host_template *sht = sdev->host->hostt;
int err = 0;
int err = 0, err2 = 0;

/* call host resume first */
if (sht->resume)
err = sht->resume(sdev);

/* then, call HLD resume */
if (drv && drv->resume)
err2 = drv->resume(dev);

scsi_device_resume(sdev);
return err;

/* favor LLD failure */
return err ? err : err2;;
}

struct bus_type scsi_bus_type = {
Expand Down
101 changes: 101 additions & 0 deletions drivers/scsi/sd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,20 @@ static ssize_t sd_store_cache_type(struct class_device *cdev, const char *buf,
return count;
}

static ssize_t sd_store_manage_start_stop(struct class_device *cdev,
const char *buf, size_t count)
{
struct scsi_disk *sdkp = to_scsi_disk(cdev);
struct scsi_device *sdp = sdkp->device;

if (!capable(CAP_SYS_ADMIN))
return -EACCES;

sdp->manage_start_stop = simple_strtoul(buf, NULL, 10);

return count;
}

static ssize_t sd_store_allow_restart(struct class_device *cdev, const char *buf,
size_t count)
{
Expand Down Expand Up @@ -179,6 +193,14 @@ static ssize_t sd_show_fua(struct class_device *cdev, char *buf)
return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
}

static ssize_t sd_show_manage_start_stop(struct class_device *cdev, char *buf)
{
struct scsi_disk *sdkp = to_scsi_disk(cdev);
struct scsi_device *sdp = sdkp->device;

return snprintf(buf, 20, "%u\n", sdp->manage_start_stop);
}

static ssize_t sd_show_allow_restart(struct class_device *cdev, char *buf)
{
struct scsi_disk *sdkp = to_scsi_disk(cdev);
Expand All @@ -192,6 +214,8 @@ static struct class_device_attribute sd_disk_attrs[] = {
__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),
__ATTR(allow_restart, S_IRUGO|S_IWUSR, sd_show_allow_restart,
sd_store_allow_restart),
__ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
sd_store_manage_start_stop),
__ATTR_NULL,
};

Expand All @@ -208,6 +232,8 @@ static struct scsi_driver sd_template = {
.name = "sd",
.probe = sd_probe,
.remove = sd_remove,
.suspend = sd_suspend,
.resume = sd_resume,
.shutdown = sd_shutdown,
},
.rescan = sd_rescan,
Expand Down Expand Up @@ -1707,13 +1733,40 @@ static void scsi_disk_release(struct class_device *cdev)
kfree(sdkp);
}

static int sd_start_stop_device(struct scsi_device *sdp, int start)
{
unsigned char cmd[6] = { START_STOP }; /* START_VALID */
struct scsi_sense_hdr sshdr;
int res;

if (start)
cmd[4] |= 1; /* START */

if (!scsi_device_online(sdp))
return -ENODEV;

res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
SD_TIMEOUT, SD_MAX_RETRIES);
if (res) {
printk(KERN_WARNING "FAILED\n status = %x, message = %02x, "
"host = %d, driver = %02x\n ",
status_byte(res), msg_byte(res),
host_byte(res), driver_byte(res));
if (driver_byte(res) & DRIVER_SENSE)
scsi_print_sense_hdr("sd", &sshdr);
}

return res;
}

/*
* Send a SYNCHRONIZE CACHE instruction down to the device through
* the normal SCSI command structure. Wait for the command to
* complete.
*/
static void sd_shutdown(struct device *dev)
{
struct scsi_device *sdp = to_scsi_device(dev);
struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);

if (!sdkp)
Expand All @@ -1723,9 +1776,57 @@ static void sd_shutdown(struct device *dev)
sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
sd_sync_cache(sdkp);
}

if (system_state != SYSTEM_RESTART && sdp->manage_start_stop) {
printk(KERN_NOTICE "Stopping disk %s: \n",
sdkp->disk->disk_name);
sd_start_stop_device(sdp, 0);
}

scsi_disk_put(sdkp);
}

static int sd_suspend(struct device *dev, pm_message_t mesg)
{
struct scsi_device *sdp = to_scsi_device(dev);
struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
int ret;

if (!sdkp)
return 0; /* this can happen */

if (sdkp->WCE) {
printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
sdkp->disk->disk_name);
ret = sd_sync_cache(sdkp);
if (ret)
return ret;
}

if (mesg.event == PM_EVENT_SUSPEND && sdp->manage_start_stop) {
printk(KERN_NOTICE "Stopping disk %s: \n",
sdkp->disk->disk_name);
ret = sd_start_stop_device(sdp, 0);
if (ret)
return ret;
}

return 0;
}

static int sd_resume(struct device *dev)
{
struct scsi_device *sdp = to_scsi_device(dev);
struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);

if (!sdp->manage_start_stop)
return 0;

printk(KERN_NOTICE "Starting disk %s: \n", sdkp->disk->disk_name);

return sd_start_stop_device(sdp, 1);
}

/**
* init_sd - entry point for this driver (both when built in or when
* a module).
Expand Down
1 change: 1 addition & 0 deletions include/scsi/scsi_device.h
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Original file line number Diff line number Diff line change
Expand Up @@ -120,6 +120,7 @@ struct scsi_device {
unsigned use_192_bytes_for_3f:1; /* ask for 192 bytes from page 0x3f */
unsigned no_start_on_add:1; /* do not issue start on add */
unsigned allow_restart:1; /* issue START_UNIT in error handler */
unsigned manage_start_stop:1; /* Let HLD (sd) manage start/stop */
unsigned no_uld_attach:1; /* disable connecting to upper level drivers */
unsigned select_no_atn:1;
unsigned fix_capacity:1; /* READ_CAPACITY is too high by 1 */
Expand Down
2 changes: 2 additions & 0 deletions include/scsi/sd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@ static void sd_rw_intr(struct scsi_cmnd * SCpnt);
static int sd_probe(struct device *);
static int sd_remove(struct device *);
static void sd_shutdown(struct device *dev);
static int sd_suspend(struct device *dev, pm_message_t state);
static int sd_resume(struct device *dev);
static void sd_rescan(struct device *);
static int sd_init_command(struct scsi_cmnd *);
static int sd_issue_flush(struct device *, sector_t *);
Expand Down

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