[PATCH 8/9] dasd: Add 'timeout' attribute

Martin Schwidefsky
2013-06-03T15:05:14Z

This patch adds a 'timeout' attibute to the DASD driver.
When set to non-zero, the blk_timeout function will
be enabled with the timeout specified in the attribute.
Setting 'timeout' to '0' will disable block timeouts.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
drivers/s390/block/dasd.c | 2 ++
drivers/s390/block/dasd_devmap.c | 56 ++++++++++++++++++++++++++++++++++++++
drivers/s390/block/dasd_int.h | 4 +++
3 files changed, 62 insertions(+)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index b97624b..54f4bb8 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2894,6 +2894,8 @@ enum blk_eh_timer_return dasd_times_out(struct request *req)
return BLK_EH_NOT_HANDLED;

device = cqr->startdev ? cqr->startdev : block->base;
+ if (!device->blk_timeout)
+ return BLK_EH_RESET_TIMER;
DBF_DEV_EVENT(DBF_WARNING, device,
" dasd_times_out cqr %p status %x",
cqr, cqr->status);
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index bc3e7af..58bc6eb 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -1280,6 +1280,61 @@ dasd_retries_store(struct device *dev, struct device_attribute *attr,

static DEVICE_ATTR(retries, 0644, dasd_retries_show, dasd_retries_store);

+static ssize_t
+dasd_timeout_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct dasd_device *device;
+ int len;
+
+ device = dasd_device_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(device))
+ return -ENODEV;
+ len = snprintf(buf, PAGE_SIZE, "%lu\n", device->blk_timeout);
+ dasd_put_device(device);
+ return len;
+}
+
+static ssize_t
+dasd_timeout_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dasd_device *device;
+ struct request_queue *q;
+ unsigned long val, flags;
+
+ device = dasd_device_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(device) || !device->block)
+ return -ENODEV;
+
+ if ((strict_strtoul(buf, 10, &val) != 0) ||
+ val > UINT_MAX / HZ) {
+ dasd_put_device(device);
+ return -EINVAL;
+ }
+ q = device->block->request_queue;
+ if (!q) {
+ dasd_put_device(device);
+ return -ENODEV;
+ }
+ spin_lock_irqsave(&device->block->request_queue_lock, flags);
+ if (!val)
+ blk_queue_rq_timed_out(q, NULL);
+ else
+ blk_queue_rq_timed_out(q, dasd_times_out);
+
+ device->blk_timeout = val;
+
+ blk_queue_rq_timeout(q, device->blk_timeout * HZ);
+ spin_unlock_irqrestore(&device->block->request_queue_lock, flags);
+
+ dasd_put_device(device);
+ return count;
+}
+
+static DEVICE_ATTR(timeout, 0644,
+ dasd_timeout_show, dasd_timeout_store);
+
static ssize_t dasd_reservation_policy_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -1391,6 +1446,7 @@ static struct attribute * dasd_attrs[] = {
&dev_attr_failfast.attr,
&dev_attr_expires.attr,
&dev_attr_retries.attr,
+ &dev_attr_timeout.attr,
&dev_attr_reservation_policy.attr,
&dev_attr_last_known_reservation_state.attr,
&dev_attr_safe_offline.attr,
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index ad42075..2bd03f4 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -470,6 +470,8 @@ struct dasd_device {
unsigned long default_expires;
unsigned long default_retries;

+ unsigned long blk_timeout;
+
struct dentry *debugfs_dentry;
struct dasd_profile profile;
};
@@ -663,6 +665,8 @@ void dasd_free_device(struct dasd_device *);
struct dasd_block *dasd_alloc_block(void);
void dasd_free_block(struct dasd_block *);

+enum blk_eh_timer_return dasd_times_out(struct request *req);
+
void dasd_enable_device(struct dasd_device *);
void dasd_set_target_state(struct dasd_device *, int);
void dasd_kick_device(struct dasd_device *);
--
1.7.9.5