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Message-Id: <20180419135655.3058-3-ubraun@linux.ibm.com>
Date: Thu, 19 Apr 2018 15:56:53 +0200
From: Ursula Braun <ubraun@...ux.ibm.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-s390@...r.kernel.org,
schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
raspl@...ux.vnet.ibm.com, ubraun@...ux.vnet.ibm.com
Subject: [PATCH net-next v2 2/4] net/smc: handle sockopt TCP_NODELAY
From: Ursula Braun <ubraun@...ux.vnet.ibm.com>
TCP sockopts set on the SMC socket must not interfere with the
CLC handshake on the internal CLC socket. Therefore, we defer some
of them till the CLC handshake has completed, like resetting
TCP_NODELAY.
While touching setsockopt, the TCP_FASTOPEN sockopts are
ignored, because SMC currently does not support Fast Open.
Signed-off-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
---
net/smc/af_smc.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
net/smc/smc.h | 4 ++
2 files changed, 123 insertions(+), 4 deletions(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 5f8046c62d90..297c2cb93b34 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -377,6 +377,24 @@ static void smc_link_save_peer_info(struct smc_link *link,
link->peer_mtu = clc->qp_mtu;
}
+/* deferred setsockopt's not desired during clc handshake */
+static int smc_apply_deferred_sockopts(struct smc_sock *smc)
+{
+ struct smc_sock *opt_smc = smc;
+ int val, rc = 0;
+
+ if (smc->listen_smc)
+ opt_smc = smc->listen_smc;
+ if (opt_smc->deferred_nodelay_reset) {
+ val = 0;
+ rc = kernel_setsockopt(smc->clcsock, SOL_TCP, TCP_NODELAY,
+ (char *)&val, sizeof(val));
+ if (!rc)
+ opt_smc->deferred_nodelay_reset = 0;
+ }
+ return rc;
+}
+
/* setup for RDMA connection of client */
static int smc_connect_rdma(struct smc_sock *smc)
{
@@ -506,6 +524,7 @@ static int smc_connect_rdma(struct smc_sock *smc)
smc_tx_init(smc);
out_connected:
+ rc = smc_apply_deferred_sockopts(smc);
smc_copy_sock_settings_to_clc(smc);
if (smc->sk.sk_state == SMC_INIT)
smc->sk.sk_state = SMC_ACTIVE;
@@ -908,6 +927,9 @@ static void smc_listen_work(struct work_struct *work)
mutex_unlock(&smc_create_lgr_pending);
out_connected:
+ rc = smc_apply_deferred_sockopts(new_smc);
+ if (rc)
+ goto out_err;
sk_refcnt_debug_inc(newsmcsk);
if (newsmcsk->sk_state == SMC_INIT)
newsmcsk->sk_state = SMC_ACTIVE;
@@ -1280,23 +1302,111 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
{
struct sock *sk = sock->sk;
struct smc_sock *smc;
+ int val, rc = 0;
smc = smc_sk(sk);
+ if (smc->use_fallback || level != SOL_TCP)
+ goto clcsock;
+
+ /* level SOL_TCP */
+ switch (optname) {
+ case TCP_CONGESTION:
+ case TCP_ULP:
+ /* sockopts without integer value; do not apply to SMC */
+ goto clcsock;
+ default:
+ break;
+ }
+
+ if (optlen < sizeof(int))
+ return -EINVAL;
+ if (get_user(val, (int __user *)optval))
+ return -EFAULT;
+
+ lock_sock(sk);
+ switch (optname) {
+ case TCP_NODELAY:
+ if (sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN) {
+ release_sock(sk);
+ goto clcsock;
+ }
+ /* for the CLC-handshake TCP_NODELAY is desired;
+ * in case of fallback to TCP, a nodelay reset is
+ * triggered afterwards.
+ */
+ if (val)
+ smc->deferred_nodelay_reset = 0;
+ else
+ smc->deferred_nodelay_reset = 1;
+ break;
+ case TCP_FASTOPEN:
+ case TCP_FASTOPEN_CONNECT:
+ case TCP_FASTOPEN_KEY:
+ case TCP_FASTOPEN_NO_COOKIE:
+ /* ignore these options; 3-way handshake shouldn't be
+ * bypassed with SMC
+ */
+ rc = -EOPNOTSUPP;
+ break;
+ default:
+ /* apply option to the CLC socket */
+ release_sock(sk);
+ goto clcsock;
+ }
+ release_sock(sk);
+ return rc;
+clcsock:
/* generic setsockopts reaching us here always apply to the
* CLC socket
*/
- return smc->clcsock->ops->setsockopt(smc->clcsock, level, optname,
- optval, optlen);
+ rc = smc->clcsock->ops->setsockopt(smc->clcsock, level, optname,
+ optval, optlen);
+ if (smc->clcsock->sk->sk_err) {
+ sk->sk_err = smc->clcsock->sk->sk_err;
+ sk->sk_error_report(sk);
+ }
+ return rc;
}
static int smc_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
+ struct sock *sk = sock->sk;
struct smc_sock *smc;
+ int val, len;
- smc = smc_sk(sock->sk);
- /* socket options apply to the CLC socket */
+ smc = smc_sk(sk);
+
+ if (smc->use_fallback || level != SOL_TCP)
+ goto clcsock;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+ len = min_t(unsigned int, len, sizeof(int));
+ if (len < 0)
+ return -EINVAL;
+
+ /* level SOL_TCP */
+ switch (optname) {
+ case TCP_NODELAY:
+ if (smc->deferred_nodelay_reset)
+ val = 0;
+ else
+ goto clcsock;
+ break;
+ default:
+ goto clcsock;
+ }
+
+ if (put_user(len, optlen))
+ return -EFAULT;
+ if (copy_to_user(optval, &val, len))
+ return -EFAULT;
+ return 0;
+
+clcsock:
+ /* socket options applying to the CLC socket */
return smc->clcsock->ops->getsockopt(smc->clcsock, level, optname,
optval, optlen);
}
@@ -1387,6 +1497,7 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,
int family = (protocol == SMCPROTO_SMC6) ? PF_INET6 : PF_INET;
struct smc_sock *smc;
struct sock *sk;
+ int val = 1;
int rc;
rc = -ESOCKTNOSUPPORT;
@@ -1412,6 +1523,10 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,
sk_common_release(sk);
goto out;
}
+ /* clc handshake should run with disabled Nagle algorithm */
+ rc = kernel_setsockopt(smc->clcsock, SOL_TCP, TCP_NODELAY, (char *)&val,
+ sizeof(val));
+ smc->deferred_nodelay_reset = 1; /* TCP_NODELAY is not the default */
smc->sk.sk_sndbuf = max(smc->clcsock->sk->sk_sndbuf, SMC_BUF_MIN_SIZE);
smc->sk.sk_rcvbuf = max(smc->clcsock->sk->sk_rcvbuf, SMC_BUF_MIN_SIZE);
diff --git a/net/smc/smc.h b/net/smc/smc.h
index e4829a2f46ba..6dfc1c90bed2 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -185,6 +185,10 @@ struct smc_sock { /* smc sock container */
* started, waiting for unsent
* data to be sent
*/
+ u8 deferred_nodelay_reset : 1;
+ /* defer Nagle after CLC
+ * handshake
+ */
};
static inline struct smc_sock *smc_sk(const struct sock *sk)
--
2.13.5
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