net/smc: make sure EPOLLOUT is raised

[ Upstream commit 4651d1802f7063e4d8c0bcad957f46ece0c04024 ]

Currently, we are only explicitly setting SOCK_NOSPACE on a write timeout
for non-blocking sockets. Epoll() edge-trigger mode relies on SOCK_NOSPACE
being set when -EAGAIN is returned to ensure that EPOLLOUT is raised.
Expand the setting of SOCK_NOSPACE to non-blocking sockets as well that can
use SO_SNDTIMEO to adjust their write timeout. This mirrors the behavior
that Eric Dumazet introduced for tcp sockets.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ursula Braun <ubraun@linux.ibm.com>
Cc: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 710ab3fbf6074ff9ce28fbb72b858ff2bb7af4ca..ec9397ec2def4044a3ec174c8f3108dc7c4e0af1 100644 (file)
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -70,13 +70,11 @@ static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
        DEFINE_WAIT_FUNC(wait, woken_wake_function);
        struct smc_connection *conn = &smc->conn;
        struct sock *sk = &smc->sk;
-       bool noblock;
        long timeo;
        int rc = 0;
 
        /* similar to sk_stream_wait_memory */
        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
-       noblock = timeo ? false : true;
        add_wait_queue(sk_sleep(sk), &wait);
        while (1) {
                sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
@@ -91,8 +89,8 @@ static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
                        break;
                }
                if (!timeo) {
-                       if (noblock)
-                               set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+                       /* ensure EPOLLOUT is subsequently generated */
+                       set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
                        rc = -EAGAIN;
                        break;
                }