[SCSI] Allow error handling timeout to be specified

Introduce eh_timeout which can be used for error handling purposes. This
was previously hardcoded to 10 seconds in the SCSI error handling
code. However, for some fast-fail scenarios it is necessary to be able
to tune this as it can take several iterations (bus device, target, bus,
controller) before we give up.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f43de1e..5624744 100644 (file)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -45,8 +45,6 @@
 
 static void scsi_eh_done(struct scsi_cmnd *scmd);
 
-#define SENSE_TIMEOUT          (10*HZ)
-
 /*
  * These should *probably* be handled by the host itself.
  * Since it is allowed to sleep, it probably should.
@@ -881,7 +879,7 @@ retry:
  */
 static int scsi_request_sense(struct scsi_cmnd *scmd)
 {
-       return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
+       return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
 }
 
 /**
@@ -982,7 +980,8 @@ static int scsi_eh_tur(struct scsi_cmnd *scmd)
        int retry_cnt = 1, rtn;
 
 retry_tur:
-       rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
+       rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
+                               scmd->device->eh_timeout, 0);
 
        SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
                __func__, scmd, rtn));

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 3e58b22..852915a 100644 (file)
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -924,6 +924,8 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
        if (*bflags & BLIST_NO_DIF)
                sdev->no_dif = 1;
 
+       sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
+
        transport_configure_device(&sdev->sdev_gendev);
 
        if (sdev->host->hostt->slave_configure) {

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 931a7d9..7e50061 100644 (file)
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -560,6 +560,35 @@ sdev_store_timeout (struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR(timeout, S_IRUGO | S_IWUSR, sdev_show_timeout, sdev_store_timeout);
 
 static ssize_t
+sdev_show_eh_timeout(struct device *dev, struct device_attribute *attr, char *buf)
+{
+       struct scsi_device *sdev;
+       sdev = to_scsi_device(dev);
+       return snprintf(buf, 20, "%u\n", sdev->eh_timeout / HZ);
+}
+
+static ssize_t
+sdev_store_eh_timeout(struct device *dev, struct device_attribute *attr,
+                   const char *buf, size_t count)
+{
+       struct scsi_device *sdev;
+       unsigned int eh_timeout;
+       int err;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EACCES;
+
+       sdev = to_scsi_device(dev);
+       err = kstrtouint(buf, 10, &eh_timeout);
+       if (err)
+               return err;
+       sdev->eh_timeout = eh_timeout * HZ;
+
+       return count;
+}
+static DEVICE_ATTR(eh_timeout, S_IRUGO | S_IWUSR, sdev_show_eh_timeout, sdev_store_eh_timeout);
+
+static ssize_t
 store_rescan_field (struct device *dev, struct device_attribute *attr,
                    const char *buf, size_t count)
 {
@@ -723,6 +752,7 @@ static struct attribute *scsi_sdev_attrs[] = {
        &dev_attr_delete.attr,
        &dev_attr_state.attr,
        &dev_attr_timeout.attr,
+       &dev_attr_eh_timeout.attr,
        &dev_attr_iocounterbits.attr,
        &dev_attr_iorequest_cnt.attr,
        &dev_attr_iodone_cnt.attr,

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 66216c1..4b87d99 100644 (file)
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -10,9 +10,14 @@
 
 #include <linux/types.h>
 #include <linux/scatterlist.h>
+#include <linux/kernel.h>
 
 struct scsi_cmnd;
 
+enum scsi_timeouts {
+       SCSI_DEFAULT_EH_TIMEOUT         = 10 * HZ,
+};
+
 /*
  * The maximum number of SG segments that we will put inside a
  * scatterlist (unless chaining is used). Should ideally fit inside a

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index cc64587..a44954c 100644 (file)
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -113,6 +113,7 @@ struct scsi_device {
                                 * scsi_devinfo.[hc]. For now used only to
                                 * pass settings from slave_alloc to scsi
                                 * core. */
+       unsigned int eh_timeout; /* Error handling timeout */
        unsigned writeable:1;
        unsigned removable:1;
        unsigned changed:1;     /* Data invalid due to media change */