net-sysfs: Use rtnl_trylock in wireless sysfs methods.

[ Upstream commit b8afe6416101549e877f8470f2a160df69676166 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 427ded841224e6b7ce79cc91158efec24ab54b4a..d5617d45deefe819d5509904d1d8c5a957c12972 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -366,7 +366,8 @@ 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)