net-sysfs: Use rtnl_trylock in wireless sysfs methods.

The wireless sysfs methods like the rest of the networking sysfs
methods are removed with the rtnl_lock held and block until
the existing methods stop executing.  So use rtnl_trylock
and restart_syscall so that the code continues to work.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index fbc1c7472c5e..099c753c4213 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -410,7 +410,8 @@ static ssize_t wireless_show(struct device *d, char *buf,
         const struct iw_statistics *iw;
         ssize_t ret = -EINVAL;
 
-        rtnl_lock();
+        if (!rtnl_trylock())
+                return restart_syscall();
         if (dev_isalive(dev)) {
                 iw = get_wireless_stats(dev);
                 if (iw)