Limit a timeout count per device. Add two parameters in scsi_device
structure, iotimeout_cnt and max_timeout_cnt. When timeout happens
on a device and returns the DRIVER_TIMEOUT error, iotimeout_cnt is
incremented. And the device is offlined when its value reaches to
max_timeout_cnt. max_timeout_cnt can be set through sysfs.
Example:
* Limit a scsi timout count to 1
# echo 1 > /sys/block/<sdX>/device/max_timeout_cnt
# cat /sys/block/<sdX>/device/max_timeout_cnt
1
* Display a current timeout count
# cat /sys/block/<sdX>/device/iotimeout_cnt
0
Signed-off-by: Takahiro Yasui <tyasui@xxxxxxxxxx>
---
drivers/scsi/scsi_error.c | 16 +++++++++++++---
drivers/scsi/scsi_scan.c | 3 +++
drivers/scsi/scsi_sysfs.c | 24 ++++++++++++++++++++++++
include/scsi/scsi_device.h | 14 ++++++++++++++
4 files changed, 54 insertions(+), 3 deletions(-)
Index: linux-2.6.30/drivers/scsi/scsi_error.c
===================================================================
--- linux-2.6.30.orig/drivers/scsi/scsi_error.c
+++ linux-2.6.30/drivers/scsi/scsi_error.c
@@ -1584,10 +1584,20 @@ void scsi_eh_flush_done_q(struct list_he
* set, do not set DRIVER_TIMEOUT.
*/
if (!scmd->result)
- scmd->result |= (DRIVER_TIMEOUT << 24);
+ set_driver_byte(scmd, DRIVER_TIMEOUT);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
- " cmd: %p\n",
- current->comm, scmd));
+ " cmd: %p\n",
+ current->comm, scmd));
+ if (scsi_device_online(scmd->device) &&
+ (driver_byte(scmd->result) & DRIVER_TIMEOUT) &&
+ scsi_check_timeout_limit(scmd->device)) {
+ sdev_printk(KERN_INFO, scmd->device,
+ "Device offlined - "
+ "reached max timeout count\n");
+ scsi_device_set_state(scmd->device,
+ SDEV_OFFLINE);
+ scsi_reset_timeout_limit(scmd->device);
+ }
scsi_finish_command(scmd);
}
}
Index: linux-2.6.30/drivers/scsi/scsi_scan.c
===================================================================
--- linux-2.6.30.orig/drivers/scsi/scsi_scan.c
+++ linux-2.6.30/drivers/scsi/scsi_scan.c
@@ -273,6 +273,9 @@ static struct scsi_device *scsi_alloc_sd
* slave_configure function */
sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
+ /* set the default timeout count (no limit) */
+ sdev->max_timeout_cnt = 0;
+
/*
* Some low level driver could use device->type
*/
Index: linux-2.6.30/drivers/scsi/scsi_sysfs.c
===================================================================
--- linux-2.6.30.orig/drivers/scsi/scsi_sysfs.c
+++ linux-2.6.30/drivers/scsi/scsi_sysfs.c
@@ -586,6 +586,27 @@ sdev_store_timeout (struct device *dev,
static DEVICE_ATTR(timeout, S_IRUGO | S_IWUSR, sdev_show_timeout, sdev_store_timeout);
static ssize_t
+sdev_show_max_timeout_cnt(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct scsi_device *sdev = to_scsi_device(dev);
+ return snprintf(buf, 20, "%d\n", sdev->max_timeout_cnt);
+}
+
+static ssize_t
+sdev_store_max_timeout_cnt(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct scsi_device *sdev = to_scsi_device(dev);
+ int val;
+ sscanf(buf, "%d\n", &val);
+ sdev->max_timeout_cnt = val;
+ return count;
+}
+static DEVICE_ATTR(max_timeout_cnt, S_IRUGO | S_IWUSR,
+ sdev_show_max_timeout_cnt, sdev_store_max_timeout_cnt);
+
+static ssize_t
store_rescan_field (struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
@@ -692,6 +713,7 @@ static DEVICE_ATTR(field, S_IRUGO, show_
show_sdev_iostat(iorequest_cnt);
show_sdev_iostat(iodone_cnt);
show_sdev_iostat(ioerr_cnt);
+show_sdev_iostat(iotimeout_cnt);
static ssize_t
sdev_show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
@@ -753,6 +775,8 @@ static struct attribute *scsi_sdev_attrs
&dev_attr_iorequest_cnt.attr,
&dev_attr_iodone_cnt.attr,
&dev_attr_ioerr_cnt.attr,
+ &dev_attr_iotimeout_cnt.attr,
+ &dev_attr_max_timeout_cnt.attr,
&dev_attr_modalias.attr,
REF_EVT(media_change),
NULL
Index: linux-2.6.30/include/scsi/scsi_device.h
===================================================================
--- linux-2.6.30.orig/include/scsi/scsi_device.h
+++ linux-2.6.30/include/scsi/scsi_device.h
@@ -155,9 +155,12 @@ struct scsi_device {
unsigned int max_device_blocked; /* what device_blocked counts down from */
#define SCSI_DEFAULT_DEVICE_BLOCKED 3
+ unsigned int max_timeout_cnt; /* max timeout count for each device */
+
atomic_t iorequest_cnt;
atomic_t iodone_cnt;
atomic_t ioerr_cnt;
+ atomic_t iotimeout_cnt;
struct device sdev_gendev,
sdev_dev;
@@ -450,6 +453,17 @@ static inline int scsi_device_protection
return sdev->scsi_level > SCSI_2 && sdev->inquiry[5] & (1<<0);
}
+static inline int scsi_check_timeout_limit(struct scsi_device *sdev)
+{
+ return atomic_inc_return(&sdev->iotimeout_cnt) ==
+ sdev->max_timeout_cnt;
+}
+
+static inline void scsi_reset_timeout_limit(struct scsi_device *sdev)
+{
+ atomic_set(&sdev->iotimeout_cnt, 0);
+}
+
#define MODULE_ALIAS_SCSI_DEVICE(type) \
MODULE_ALIAS("scsi:t-" __stringify(type) "*")
#define SCSI_DEVICE_MODALIAS_FMT "scsi:t-0x%02x"
--
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