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path: root/drivers/s390/cio/ccwgroup.c
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Diffstat (limited to 'drivers/s390/cio/ccwgroup.c')
-rw-r--r--drivers/s390/cio/ccwgroup.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 3ac2c2019f5..918e6fce257 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -19,6 +19,8 @@
#include <asm/ccwdev.h>
#include <asm/ccwgroup.h>
+#define CCW_BUS_ID_SIZE 20
+
/* In Linux 2.4, we had a channel device layer called "chandev"
* that did all sorts of obscure stuff for networking devices.
* This is another driver that serves as a replacement for just
@@ -89,15 +91,23 @@ ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const
gdev = to_ccwgroupdev(dev);
- if (gdev->state != CCWGROUP_OFFLINE)
- return -EINVAL;
-
+ /* Prevent concurrent online/offline processing and ungrouping. */
+ if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
+ return -EAGAIN;
+ if (gdev->state != CCWGROUP_OFFLINE) {
+ rc = -EINVAL;
+ goto out;
+ }
/* Note that we cannot unregister the device from one of its
* attribute methods, so we have to use this roundabout approach.
*/
rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
- if (rc)
- count = rc;
+out:
+ if (rc) {
+ /* Release onoff "lock" when ungrouping failed. */
+ atomic_set(&gdev->onoff, 0);
+ return rc;
+ }
return count;
}
@@ -172,7 +182,7 @@ static int __get_next_bus_id(const char **buf, char *bus_id)
len = end - start + 1;
end++;
}
- if (len < BUS_ID_SIZE) {
+ if (len < CCW_BUS_ID_SIZE) {
strlcpy(bus_id, start, len);
rc = 0;
} else
@@ -181,7 +191,7 @@ static int __get_next_bus_id(const char **buf, char *bus_id)
return rc;
}
-static int __is_valid_bus_id(char bus_id[BUS_ID_SIZE])
+static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
{
int cssid, ssid, devno;
@@ -213,7 +223,7 @@ int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
{
struct ccwgroup_device *gdev;
int rc, i;
- char tmp_bus_id[BUS_ID_SIZE];
+ char tmp_bus_id[CCW_BUS_ID_SIZE];
const char *curr_buf;
gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),