summaryrefslogtreecommitdiff
path: root/drivers/s390/block/dasd_devmap.c
diff options
context:
space:
mode:
authorJan Höppner <hoeppner@linux.vnet.ibm.com>2016-10-12 12:51:04 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-10-28 10:09:04 +0200
commit9de67725c80cb8a7b34b1932e196d2ed61a08879 (patch)
tree3a29c6b57286e62cd550542abcddde4c8fde34bc /drivers/s390/block/dasd_devmap.c
parent0f57c97f241b4fc18251fb2b1c499e9f71e93c78 (diff)
s390/dasd: Fix locking issue when changing EER attribute
The reference to a device in question may get lost when the extended error reporting (EER) attribute is being enabled/disabled while the device is set offline at the same time. This is due to missing refcounting and incorrect locking. Fix this by the following: - In dasd_eer_store() get the device directly and handle the refcount accordingly. - Move the lock in dasd_eer_enable() up so we can ensure safe processing. - Check if the device is being set offline and return with -EBUSY if so. - While at it, change the return code from -EPERM to -EMEDIUMTYPE as suggested by a FIXME, since that is what we're actually checking. Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/block/dasd_devmap.c')
-rw-r--r--drivers/s390/block/dasd_devmap.c27
1 files changed, 13 insertions, 14 deletions
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 221d8c8e63d5..c1979ecce821 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -1167,26 +1167,25 @@ static ssize_t
dasd_eer_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
- struct dasd_devmap *devmap;
+ struct dasd_device *device;
unsigned int val;
- int rc;
+ int rc = 0;
- devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
- if (IS_ERR(devmap))
- return PTR_ERR(devmap);
- if (!devmap->device)
- return -ENODEV;
+ device = dasd_device_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(device))
+ return PTR_ERR(device);
if (kstrtouint(buf, 0, &val) || val > 1)
return -EINVAL;
- if (val) {
- rc = dasd_eer_enable(devmap->device);
- if (rc)
- return rc;
- } else
- dasd_eer_disable(devmap->device);
- return count;
+ if (val)
+ rc = dasd_eer_enable(device);
+ else
+ dasd_eer_disable(device);
+
+ dasd_put_device(device);
+
+ return rc ? : count;
}
static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);