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| author | Vincent Whitchurch <vincent.whitchurch@axis.com> | 2018-09-06 15:54:59 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-09-07 23:11:06 -0700 |
| commit | 5cf4a8532c992bb22a9ecd5f6d93f873f4eaccc2 (patch) | |
| tree | c3a217b0a679c4821e045f32ddfff995b0dc5b9d /net/ipv4/tcp.c | |
| parent | a162c3511410b50f09c002fea56fea2153b679d0 (diff) | |
| download | linux-5cf4a8532c992bb22a9ecd5f6d93f873f4eaccc2.tar.gz linux-5cf4a8532c992bb22a9ecd5f6d93f873f4eaccc2.tar.bz2 linux-5cf4a8532c992bb22a9ecd5f6d93f873f4eaccc2.zip | |
tcp: really ignore MSG_ZEROCOPY if no SO_ZEROCOPY
According to the documentation in msg_zerocopy.rst, the SO_ZEROCOPY
flag was introduced because send(2) ignores unknown message flags and
any legacy application which was accidentally passing the equivalent of
MSG_ZEROCOPY earlier should not see any new behaviour.
Before commit f214f915e7db ("tcp: enable MSG_ZEROCOPY"), a send(2) call
which passed the equivalent of MSG_ZEROCOPY without setting SO_ZEROCOPY
would succeed. However, after that commit, it fails with -ENOBUFS. So
it appears that the SO_ZEROCOPY flag fails to fulfill its intended
purpose. Fix it.
Fixes: f214f915e7db ("tcp: enable MSG_ZEROCOPY")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index b8af2fec5ad5..10c6246396cc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1185,7 +1185,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) flags = msg->msg_flags; - if (flags & MSG_ZEROCOPY && size) { + if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) { if (sk->sk_state != TCP_ESTABLISHED) { err = -EINVAL; goto out_err; |