[PATCH] Make SCSI timeout modifiable

add a timeout field to struct scsi_device and expose it in in sysfs.

This patch allows LLDs to override the default timeout used for scsi devices
and exposes it in sysfs. The default timeout value used is too short for
many RAID array devices, such as those created by the ipr driver.

drivers/scsi/scsi_sysfs.c

@@ -302,6 +302,26 @@ sdev_rd_attr (vendor, "%.8s\n");
 sdev_rd_attr (model, "%.16s\n");
 sdev_rd_attr (rev, "%.4s\n");
 
+static ssize_t
+sdev_show_timeout (struct device *dev, char *buf)
+{
+	struct scsi_device *sdev;
+	sdev = to_scsi_device(dev);
+	return snprintf (buf, 20, "%d\n", sdev->timeout / HZ);
+}
+
+static ssize_t
+sdev_store_timeout (struct device *dev, const char *buf, size_t count)
+{
+	struct scsi_device *sdev;
+	int timeout;
+	sdev = to_scsi_device(dev);
+	sscanf (buf, "%d\n", &timeout);
+	sdev->timeout = timeout * HZ;
+	return count;
+}
+static DEVICE_ATTR(timeout, S_IRUGO | S_IWUSR, sdev_show_timeout, sdev_store_timeout)
+
 static ssize_t
 store_rescan_field (struct device *dev, const char *buf, size_t count) 
 {
@@ -368,6 +388,7 @@ static struct device_attribute *scsi_sysfs_sdev_attrs[] = {
 	&dev_attr_rescan,
 	&dev_attr_delete,
 	&dev_attr_state,
+	&dev_attr_timeout,
 	NULL
 };
 

drivers/scsi/sd.c

@@ -217,9 +217,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	sector_t block;
 	struct scsi_device *sdp = SCpnt->device;
 
-	timeout = SD_TIMEOUT;
-	if (SCpnt->device->type != TYPE_DISK)
-		timeout = SD_MOD_TIMEOUT;
+	timeout = sdp->timeout;
 
 	/*
 	 * these are already setup, just copy cdb basically
@@ -1389,6 +1387,13 @@ static int sd_probe(struct device *dev)
 	sdkp->index = index;
 	sdkp->openers = 0;
 
+	if (!sdp->timeout) {
+		if (sdp->type == TYPE_DISK)
+			sdp->timeout = SD_TIMEOUT;
+		else
+			sdp->timeout = SD_MOD_TIMEOUT;
+	}
+
 	devno = make_sd_dev(index, 0);
 	gd->major = MAJOR(devno);
 	gd->first_minor = MINOR(devno);

include/scsi/scsi_device.h

@@ -112,6 +112,8 @@ struct scsi_device {
 	unsigned int max_device_blocked; /* what device_blocked counts down from  */
 #define SCSI_DEFAULT_DEVICE_BLOCKED	3
 
+	int timeout;
+
 	struct device		sdev_gendev;
 	struct class_device	sdev_classdev;