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Date: Tue, 17 Apr 2018 17:18:14 +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 3/4] net/smc: handle sockopt TCP_CORK
From: Ursula Braun <ubraun@...ux.vnet.ibm.com>
TCP sockopts must not interfere with the CLC handshake on the
CLC socket. Therefore, we defer some of them till the CLC
handshake has completed, like setting TCP_CORK.
For a corked SMC socket RDMA writes are deferred, if there is
still sufficient send buffer space available.
Signed-off-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
---
net/smc/af_smc.c | 32 ++++++++++++++++++++++++++++++++
net/smc/smc.h | 4 ++++
net/smc/smc_tx.c | 16 +++++++++++++---
net/smc/smc_tx.h | 8 ++++++++
4 files changed, 57 insertions(+), 3 deletions(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 96f4d182f998..c3a950c6950d 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -391,6 +391,12 @@ static void smc_apply_deferred_sockopts(struct smc_sock *smc)
sizeof(val));
opt_smc->deferred_nodelay_reset = 0;
}
+ if (opt_smc->deferred_cork_set) {
+ val = 1;
+ kernel_setsockopt(smc->clcsock, SOL_TCP, TCP_CORK, &val,
+ sizeof(val));
+ opt_smc->deferred_cork_set = 0;
+ }
}
/* setup for RDMA connection of client */
@@ -1323,6 +1329,9 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
switch (optname) {
case TCP_NODELAY:
if (sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN) {
+ if (val && smc_tx_is_corked(smc))
+ mod_delayed_work(system_wq, &smc->conn.tx_work,
+ 0);
release_sock(sk);
goto clcsock;
}
@@ -1335,6 +1344,23 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
else
smc->deferred_nodelay_reset = 1;
break;
+ case TCP_CORK:
+ if (sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN) {
+ if (!val)
+ mod_delayed_work(system_wq, &smc->conn.tx_work,
+ 0);
+ release_sock(sk);
+ goto clcsock;
+ }
+ /* for the CLC-handshake TCP_CORK is not desired;
+ * in case of fallback to TCP, cork setting is
+ * triggered afterwards.
+ */
+ if (val)
+ smc->deferred_cork_set = 1;
+ else
+ smc->deferred_cork_set = 0;
+ break;
case TCP_FASTOPEN:
case TCP_FASTOPEN_CONNECT:
case TCP_FASTOPEN_KEY:
@@ -1385,6 +1411,12 @@ static int smc_getsockopt(struct socket *sock, int level, int optname,
else
goto clcsock;
break;
+ case TCP_CORK:
+ if (smc->deferred_cork_set)
+ val = 1;
+ else
+ goto clcsock;
+ break;
default:
goto clcsock;
}
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 6dfc1c90bed2..38888da5a5ea 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -189,6 +189,10 @@ struct smc_sock { /* smc sock container */
/* defer Nagle after CLC
* handshake
*/
+ u8 deferred_cork_set : 1;
+ /* defer corking after CLC
+ * handshake
+ */
};
static inline struct smc_sock *smc_sk(const struct sock *sk)
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 72f004c9c9b1..a31377bb400b 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -26,6 +26,7 @@
#include "smc_tx.h"
#define SMC_TX_WORK_DELAY HZ
+#define SMC_TX_CORK_DELAY (HZ >> 2) /* 250 ms */
/***************************** sndbuf producer *******************************/
@@ -209,7 +210,16 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
/* since we just produced more new data into sndbuf,
* trigger sndbuf consumer: RDMA write into peer RMBE and CDC
*/
- smc_tx_sndbuf_nonempty(conn);
+ if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) &&
+ (atomic_read(&conn->sndbuf_space) >
+ (conn->sndbuf_size >> 1)))
+ /* for a corked socket defer the RDMA writes if there
+ * is still sufficient sndbuf_space available
+ */
+ schedule_delayed_work(&conn->tx_work,
+ SMC_TX_CORK_DELAY);
+ else
+ smc_tx_sndbuf_nonempty(conn);
} /* while (msg_data_left(msg)) */
return send_done;
@@ -409,8 +419,8 @@ int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
}
rc = 0;
if (conn->alert_token_local) /* connection healthy */
- schedule_delayed_work(&conn->tx_work,
- SMC_TX_WORK_DELAY);
+ mod_delayed_work(system_wq, &conn->tx_work,
+ SMC_TX_WORK_DELAY);
}
goto out_unlock;
}
diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h
index 78255964fa4d..e5f4188b4bdb 100644
--- a/net/smc/smc_tx.h
+++ b/net/smc/smc_tx.h
@@ -14,6 +14,7 @@
#include <linux/socket.h>
#include <linux/types.h>
+#include <net/tcp.h>
#include "smc.h"
#include "smc_cdc.h"
@@ -27,6 +28,13 @@ static inline int smc_tx_prepared_sends(struct smc_connection *conn)
return smc_curs_diff(conn->sndbuf_size, &sent, &prep);
}
+static inline bool smc_tx_is_corked(struct smc_sock *smc)
+{
+ struct tcp_sock *tp = tcp_sk(smc->clcsock->sk);
+
+ return (tp->nonagle & TCP_NAGLE_CORK) ? true : false;
+}
+
void smc_tx_init(struct smc_sock *smc);
int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len);
int smc_tx_sndbuf_nonempty(struct smc_connection *conn);
--
2.13.5
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