diff options
Diffstat (limited to 'drivers/s390/cio/ccwgroup.c')
| -rw-r--r-- | drivers/s390/cio/ccwgroup.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c index 3ac2c2019f5e..918e6fce2573 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]), |