[TCP]: Fix sk_forward_alloc underflow in tcp_sendmsg
I've finally found a potential cause of the sk_forward_alloc underflows
that people have been reporting sporadically.
When tcp_sendmsg tacks on extra bits to an existing TCP_PAGE we don't
check sk_forward_alloc even though a large amount of time may have
elapsed since we allocated the page. In the mean time someone could've
come along and liberated packets and reclaimed sk_forward_alloc memory.
This patch makes tcp_sendmsg check sk_forward_alloc every time as we
do in do_tcp_sendpages.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index e51e626..cf62826 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1232,9 +1232,8 @@
{
struct page *page = NULL;
- if (sk_stream_wmem_schedule(sk, PAGE_SIZE))
- page = alloc_pages(sk->sk_allocation, 0);
- else {
+ page = alloc_pages(sk->sk_allocation, 0);
+ if (!page) {
sk->sk_prot->enter_memory_pressure();
sk_stream_moderate_sndbuf(sk);
}