From 5e18247b02d60a1ea4bf98c05e139461ca9aec64 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 18 Jan 2011 13:04:43 +0200 Subject: [PATCH] vhost: rcu annotation fixup When built with rcu checks enabled, vhost triggers bogus warnings as vhost features are read without dev->mutex sometimes, and private pointer is read with our kind of rcu where work serves as a read side critical section. Fixing it properly is not trivial. Disable the warnings by stubbing out the checks for now. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/net.c | 9 +++++---- drivers/vhost/vhost.h | 6 +++--- 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 9b3ca103135f..f616cefc95ba 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -128,8 +128,7 @@ static void handle_tx(struct vhost_net *net) size_t hdr_size; struct socket *sock; - /* TODO: check that we are running from vhost_worker? - * Not sure it's worth it, it's straight-forward enough. */ + /* TODO: check that we are running from vhost_worker? */ sock = rcu_dereference_check(vq->private_data, 1); if (!sock) return; @@ -306,7 +305,8 @@ static void handle_rx_big(struct vhost_net *net) size_t len, total_len = 0; int err; size_t hdr_size; - struct socket *sock = rcu_dereference(vq->private_data); + /* TODO: check that we are running from vhost_worker? */ + struct socket *sock = rcu_dereference_check(vq->private_data, 1); if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) return; @@ -415,7 +415,8 @@ static void handle_rx_mergeable(struct vhost_net *net) int err, headcount; size_t vhost_hlen, sock_hlen; size_t vhost_len, sock_len; - struct socket *sock = rcu_dereference(vq->private_data); + /* TODO: check that we are running from vhost_worker? */ + struct socket *sock = rcu_dereference_check(vq->private_data, 1); if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue)) return; diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 2af44b7b1f3f..b3363ae38518 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -173,9 +173,9 @@ static inline int vhost_has_feature(struct vhost_dev *dev, int bit) { unsigned acked_features; - acked_features = - rcu_dereference_index_check(dev->acked_features, - lockdep_is_held(&dev->mutex)); + /* TODO: check that we are running from vhost_worker or dev mutex is + * held? */ + acked_features = rcu_dereference_index_check(dev->acked_features, 1); return acked_features & (1 << bit); } -- 2.20.1