diff options
| author |   jbaron@akamai.com <jbaron@akamai.com> | 2015-04-20 20:05:07 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2015-04-21 15:57:34 -0400 |
| commit | 3c7151275c0c9a80c3375f9874b1c7129a105eea (patch) | |
| tree | d1c703725e11d908f2d027dd62c22f83bc1e0c19 /net/ipv4/tcp.c | |
| parent | altera tse: Error-Bit on tx-avalon-stream always set. (diff) | |
| download | linux-dev-3c7151275c0c9a80c3375f9874b1c7129a105eea.tar.xz linux-dev-3c7151275c0c9a80c3375f9874b1c7129a105eea.zip | |
tcp: add memory barriers to write space paths
Ensure that we either see that the buffer has write space
in tcp_poll() or that we perform a wakeup from the input
side. Did not run into any actual problem here, but thought
that we should make things explicit.
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 59c8a027721b..8c5cd9efebbc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -520,8 +520,10 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) /* Race breaker. If space is freed after * wspace test but before the flags are set, - * IO signal will be lost. + * IO signal will be lost. Memory barrier + * pairs with the input side. */ + smp_mb__after_atomic(); if (sk_stream_is_writeable(sk)) mask |= POLLOUT | POLLWRNORM; } |