[PATCH 3/6] udp: Add annotations for udp_rmem_release()

Jules Irenge
2020-04-29T10:07:10Z

Sparse reports a warning

warning: context imbalance in udp_rmem_release() - unexpected unlock

To fix this,
__acquire(&sk_queue->lock) and __release(&sk_queue->lock) annotations
are added in case the condition is not met.

This add basically tell Sparse and not GCC to shutdown the warning

Add __acquire(&sk_queue->lock) annotation
Add the __release(&sk_queue->lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
---
net/ipv4/udp.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5ca12a945ac3..175bd14bfac8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1382,6 +1382,9 @@ static void udp_rmem_release(struct sock *sk, int size, int partial,
sk_queue = &sk->sk_receive_queue;
if (!rx_queue_lock_held)
spin_lock(&sk_queue->lock);
+ else
+ /* annotation for sparse */
+ __acquire(&sk_queue->lock);

sk->sk_forward_alloc += size;
@@ -1398,6 +1401,9 @@ static void udp_rmem_release(struct sock *sk, int size, int partial,

if (!rx_queue_lock_held)
spin_unlock(&sk_queue->lock);
+ else
+ /* annotation for sparse */
+ __release(&sk_queue->lock);
}

/* Note: called with reader_queue.lock held.
--
2.25.3