IB/cma: Add a missing rcu_read_unlock()

Ensure that validate_ipv4_net_dev() calls rcu_read_unlock() if
fib_lookup() fails. Detected by sparse. Compile-tested only.

Fixes: "IB/cma: Validate routing of incoming requests" (commit f887f2ac87c2).
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 944cd90417bcc9b2a51d27f903feffad6f2307ea..d2d5d004f16dbb11fc4a57b5ce47004da567a137 100644 (file)
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -1126,10 +1126,7 @@ static bool validate_ipv4_net_dev(struct net_device *net_dev,
 
        rcu_read_lock();
        err = fib_lookup(dev_net(net_dev), &fl4, &res, 0);
-       if (err)
-               return false;
-
-       ret = FIB_RES_DEV(res) == net_dev;
+       ret = err == 0 && FIB_RES_DEV(res) == net_dev;
        rcu_read_unlock();
 
        return ret;