[PATCH net-next 3/4] net/smc: urgent data support

Ursula Braun
2018-05-23T14:38:11Z

From: Stefan Raspl <raspl@linux.ibm.com>

Add support for out of band data send and receive.

Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/af_smc.c | 24 ++++++++++-
net/smc/smc.h | 15 +++++++
net/smc/smc_cdc.c | 44 ++++++++++++++++++--
net/smc/smc_cdc.h | 13 ++++++
net/smc/smc_core.c | 1 +
net/smc/smc_rx.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++------
net/smc/smc_tx.c | 55 ++++++++++++++++--------
net/smc/smc_tx.h | 2 +-
8 files changed, 238 insertions(+), 36 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f2d925921d81..2c369d4bb1c1 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -8,8 +8,6 @@
*
* Initial restrictions:
* - support for alternate links postponed
- * - partial support for non-blocking sockets only
- * - support for urgent data postponed
*
* Copyright IBM Corp. 2016, 2018
*
@@ -1338,6 +1336,8 @@ static __poll_t smc_poll(struct file *file, struct socket *sock,
if (sk->sk_state == SMC_APPCLOSEWAIT1)
mask |= EPOLLIN;
}
+ if (smc->conn.urg_state == SMC_URG_VALID)
+ mask |= EPOLLPRI;

}
release_sock(sk);
@@ -1477,10 +1477,13 @@ static int smc_getsockopt(struct socket *sock, int level, int optname,
static int smc_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg)
{
+ union smc_host_cursor cons, urg;
+ struct smc_connection *conn;
struct smc_sock *smc;
int answ;

smc = smc_sk(sock->sk);
+ conn = &smc->conn;
if (smc->use_fallback) {
if (!smc->clcsock)
return -EBADF;
@@ -1517,6 +1520,23 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd,
else
answ = smc_tx_prepared_sends(&smc->conn);
break;
+ case SIOCATMARK:
+ if (smc->sk.sk_state == SMC_LISTEN)
+ return -EINVAL;
+ if (smc->sk.sk_state == SMC_INIT ||
+ smc->sk.sk_state == SMC_CLOSED) {
+ answ = 0;
+ } else {
+ smc_curs_write(&cons,
+ smc_curs_read(&conn->local_tx_ctrl.cons, conn),
+ conn);
+ smc_curs_write(&urg,
+ smc_curs_read(&conn->urg_curs, conn),
+ conn);
+ answ = smc_curs_diff(conn->rmb_desc->len,
+ &cons, &urg) == 1;
+ }
+ break;
default:
return -ENOIOCTLCMD;
}
diff --git a/net/smc/smc.h b/net/smc/smc.h
index a1467e411645..51ae1f10d81a 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -114,6 +114,12 @@ struct smc_host_cdc_msg { /* Connection Data Control message */
u8 reserved[18];
} __aligned(8);

+enum smc_urg_state {
+ SMC_URG_VALID, /* data present */
+ SMC_URG_NOTYET, /* data pending */
+ SMC_URG_READ /* data was already read */
+};
+
struct smc_connection {
struct rb_node alert_node;
struct smc_link_group *lgr; /* link group of connection */
@@ -160,6 +166,15 @@ struct smc_connection {
union smc_host_cursor rx_curs_confirmed; /* confirmed to peer
* source of snd_una ?
*/
+ union smc_host_cursor urg_curs; /* points at urgent byte */
+ enum smc_urg_state urg_state;
+ bool urg_tx_pend; /* urgent data staged */
+ bool urg_rx_skip_pend;
+ /* indicate urgent oob data
+ * read, but previous regular
+ * data still pending
+ */
+ char urg_rx_byte; /* urgent byte */
atomic_t bytes_to_rcv; /* arrived data,
* not yet received
*/
diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index 8d2c079c87b0..a7e8d63fc8ae 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -164,6 +164,28 @@ static inline bool smc_cdc_before(u16 seq1, u16 seq2)
return (s16)(seq1 - seq2) < 0;
}

+static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
+ int *diff_prod)
+{
+ struct smc_connection *conn = &smc->conn;
+ char *base;
+
+ /* new data included urgent business */
+ smc_curs_write(&conn->urg_curs,
+ smc_curs_read(&conn->local_rx_ctrl.prod, conn),
+ conn);
+ conn->urg_state = SMC_URG_VALID;
+ if (!sock_flag(&smc->sk, SOCK_URGINLINE))
+ /* we'll skip the urgent byte, so don't account for it */
+ (*diff_prod)--;
+ base = (char *)conn->rmb_desc->cpu_addr;
+ if (conn->urg_curs.count)
+ conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
+ else
+ conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
+ sk_send_sigurg(&smc->sk);
+}
+
static void smc_cdc_msg_recv_action(struct smc_sock *smc,
struct smc_cdc_msg *cdc)
{
@@ -194,15 +216,25 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc,
diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
&conn->local_rx_ctrl.prod);
if (diff_prod) {
+ if (conn->local_rx_ctrl.prod_flags.urg_data_present)
+ smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
/* bytes_to_rcv is decreased in smc_recvmsg */
smp_mb__before_atomic();
atomic_add(diff_prod, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
smp_mb__after_atomic();
smc->sk.sk_data_ready(&smc->sk);
- } else if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
- (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req)) {
- smc->sk.sk_data_ready(&smc->sk);
+ } else {
+ if (conn->local_rx_ctrl.prod_flags.write_blocked ||
+ conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
+ conn->local_rx_ctrl.prod_flags.urg_data_pending) {
+ if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
+ conn->urg_state = SMC_URG_NOTYET;
+ /* force immediate tx of current consumer cursor, but
+ * under send_lock to guarantee arrival in seqno-order
+ */
+ smc_tx_sndbuf_nonempty(conn);
+ }
}

/* piggy backed tx info */
@@ -212,6 +244,12 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc,
/* trigger socket release if connection closed */
smc_close_wake_tx_prepared(smc);
}
+ if (diff_cons && conn->urg_tx_pend &&
+ atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
+ /* urg data confirmed by peer, indicate we're ready for more */
+ conn->urg_tx_pend = false;
+ smc->sk.sk_write_space(&smc->sk);
+ }

if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
smc->sk.sk_err = ECONNRESET;
diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
index d2012fd22100..f60082fee5b8 100644
--- a/net/smc/smc_cdc.h
+++ b/net/smc/smc_cdc.h
@@ -146,6 +146,19 @@ static inline int smc_curs_diff(unsigned int size,
return max_t(int, 0, (new->count - old->count));
}

+/* calculate cursor difference between old and new - returns negative
+ * value in case old > new
+ */
+static inline int smc_curs_comp(unsigned int size,
+ union smc_host_cursor *old,
+ union smc_host_cursor *new)
+{
+ if (old->wrap > new->wrap ||
+ (old->wrap == new->wrap && old->count > new->count))
+ return -smc_curs_diff(size, new, old);
+ return smc_curs_diff(size, old, new);
+}
+
static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
union smc_host_cursor *local,
struct smc_connection *conn)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 21c244f53b0a..2bf138e7d3ec 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -544,6 +544,7 @@ int smc_conn_create(struct smc_sock *smc,
}
conn->local_tx_ctrl.common.type = SMC_CDC_MSG_TYPE;
conn->local_tx_ctrl.len = SMC_WR_TX_SIZE;
+ conn->urg_state = SMC_URG_READ;
#ifndef KERNEL_HAS_ATOMIC64
spin_lock_init(&conn->acurs_lock);
#endif
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 290a434471d1..3d77b383cccd 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -47,16 +47,59 @@ static void smc_rx_wake_up(struct sock *sk)
* @conn connection to update
* @cons consumer cursor
* @len number of Bytes consumed
+ * Returns:
+ * 1 if we should end our receive, 0 otherwise
*/
-static void smc_rx_update_consumer(struct smc_connection *conn,
- union smc_host_cursor cons, size_t len)
+static int smc_rx_update_consumer(struct smc_sock *smc,
+ union smc_host_cursor cons, size_t len)
{
+ struct smc_connection *conn = &smc->conn;
+ struct sock *sk = &smc->sk;
+ bool force = false;
+ int diff, rc = 0;
+
smc_curs_add(conn->rmb_desc->len, &cons, len);
+
+ /* did we process urgent data? */
+ if (conn->urg_state == SMC_URG_VALID || conn->urg_rx_skip_pend) {
+ diff = smc_curs_comp(conn->rmb_desc->len, &cons,
+ &conn->urg_curs);
+ if (sock_flag(sk, SOCK_URGINLINE)) {
+ if (diff == 0) {
+ force = true;
+ rc = 1;
+ conn->urg_state = SMC_URG_READ;
+ }
+ } else {
+ if (diff == 1) {
+ /* skip urgent byte */
+ force = true;
+ smc_curs_add(conn->rmb_desc->len, &cons, 1);
+ conn->urg_rx_skip_pend = false;
+ } else if (diff < -1)
+ /* we read past urgent byte */
+ conn->urg_state = SMC_URG_READ;
+ }
+ }
+
smc_curs_write(&conn->local_tx_ctrl.cons, smc_curs_read(&cons, conn),
conn);
+
/* send consumer cursor update if required */
/* similar to advertising new TCP rcv_wnd if required */
- smc_tx_consumer_update(conn);
+ smc_tx_consumer_update(conn, force);
+
+ return rc;
+}
+
+static void smc_rx_update_cons(struct smc_sock *smc, size_t len)
+{
+ struct smc_connection *conn = &smc->conn;
+ union smc_host_cursor cons;
+
+ smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn),
+ conn);
+ smc_rx_update_consumer(smc, cons, len);
}

struct smc_spd_priv {
@@ -70,7 +113,6 @@ static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe,
struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private;
struct smc_sock *smc = priv->smc;
struct smc_connection *conn;
- union smc_host_cursor cons;
struct sock *sk = &smc->sk;

if (sk->sk_state == SMC_CLOSED ||
@@ -79,9 +121,7 @@ static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe,
goto out;
conn = &smc->conn;
lock_sock(sk);
- smc_curs_write(&cons, smc_curs_read(&conn->local_tx_ctrl.cons, conn),
- conn);
- smc_rx_update_consumer(conn, cons, priv->len);
+ smc_rx_update_cons(smc, priv->len);
release_sock(sk);
if (atomic_sub_and_test(priv->len, &conn->splice_pending))
smc_rx_wake_up(sk);
@@ -184,6 +224,52 @@ int smc_rx_wait(struct smc_sock *smc, long *timeo,
return rc;
}

+static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len,
+ int flags)
+{
+ struct smc_connection *conn = &smc->conn;
+ union smc_host_cursor cons;
+ struct sock *sk = &smc->sk;
+ int rc = 0;
+
+ if (sock_flag(sk, SOCK_URGINLINE) ||
+ !(conn->urg_state == SMC_URG_VALID) ||
+ conn->urg_state == SMC_URG_READ)
+ return -EINVAL;
+
+ if (conn->urg_state == SMC_URG_VALID) {
+ if (!(flags & MSG_PEEK))
+ smc->conn.urg_state = SMC_URG_READ;
+ msg->msg_flags |= MSG_OOB;
+ if (len > 0) {
+ if (!(flags & MSG_TRUNC))
+ rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1);
+ len = 1;
+ smc_curs_write(&cons,
+ smc_curs_read(&conn->local_tx_ctrl.cons,
+ conn),
+ conn);
+ if (smc_curs_diff(conn->rmb_desc->len, &cons,
+ &conn->urg_curs) > 1)
+ conn->urg_rx_skip_pend = true;
+ /* Urgent Byte was already accounted for, but trigger
+ * skipping the urgent byte in non-inline case
+ */
+ if (!(flags & MSG_PEEK))
+ smc_rx_update_consumer(smc, cons, 0);
+ } else {
+ msg->msg_flags |= MSG_TRUNC;
+ }
+
+ return rc ? -EFAULT : len;
+ }
+
+ if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN)
+ return 0;
+
+ return -EAGAIN;
+}
+
/* smc_rx_recvmsg - receive data from RMBE
* @msg: copy data to receive buffer
* @pipe: copy data to pipe if set - indicates splice() call
@@ -209,12 +295,12 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,

if (unlikely(flags & MSG_ERRQUEUE))
return -EINVAL; /* future work for sk.sk_family == AF_SMC */
- if (flags & MSG_OOB)
- return -EINVAL; /* future work */

sk = &smc->sk;
if (sk->sk_state == SMC_LISTEN)
return -ENOTCONN;
+ if (flags & MSG_OOB)
+ return smc_rx_recv_urg(smc, msg, len, flags);
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);

@@ -227,6 +313,9 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,

if (atomic_read(&conn->bytes_to_rcv))
goto copy;
+ else if (conn->urg_state == SMC_URG_VALID)
+ /* we received a single urgent Byte - skip */
+ smc_rx_update_cons(smc, 0);

if (sk->sk_shutdown & RCV_SHUTDOWN ||
smc_cdc_rxed_any_close_or_senddone(conn) ||
@@ -281,14 +370,18 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
continue;
}

- /* not more than what user space asked for */
- copylen = min_t(size_t, read_remaining, readable);
smc_curs_write(&cons,
smc_curs_read(&conn->local_tx_ctrl.cons, conn),
conn);
/* subsequent splice() calls pick up where previous left */
if (splbytes)
smc_curs_add(conn->rmb_desc->len, &cons, splbytes);
+ if (conn->urg_state == SMC_URG_VALID &&
+ sock_flag(&smc->sk, SOCK_URGINLINE) &&
+ readable > 1)
+ readable--; /* always stop at urgent Byte */
+ /* not more than what user space asked for */
+ copylen = min_t(size_t, read_remaining, readable);
/* determine chunks where to read from rcvbuf */
/* either unwrapped case, or 1st chunk of wrapped case */
chunk_len = min_t(size_t, copylen, conn->rmb_desc->len -
@@ -333,8 +426,8 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
atomic_sub(copylen, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
smp_mb__after_atomic();
- if (msg)
- smc_rx_update_consumer(conn, cons, copylen);
+ if (msg && smc_rx_update_consumer(smc, cons, copylen))
+ goto out;
}
} while (read_remaining);
out:
@@ -346,4 +439,5 @@ void smc_rx_init(struct smc_sock *smc)
{
smc->sk.sk_data_ready = smc_rx_wake_up;
atomic_set(&smc->conn.splice_pending, 0);
+ smc->conn.urg_state = SMC_URG_READ;
}
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 1f4a38b857f0..cee666400752 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -32,7 +32,7 @@
/***************************** sndbuf producer *******************************/

/* callback implementation for sk.sk_write_space()
- * to wakeup sndbuf producers that blocked with smc_tx_wait_memory().
+ * to wakeup sndbuf producers that blocked with smc_tx_wait().
* called under sk_socket lock.
*/
static void smc_tx_write_space(struct sock *sk)
@@ -56,7 +56,7 @@ static void smc_tx_write_space(struct sock *sk)
}
}

-/* Wakeup sndbuf producers that blocked with smc_tx_wait_memory().
+/* Wakeup sndbuf producers that blocked with smc_tx_wait().
* Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
*/
void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
@@ -66,8 +66,10 @@ void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
smc->sk.sk_write_space(&smc->sk);
}

-/* blocks sndbuf producer until at least one byte of free space available */
-static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
+/* blocks sndbuf producer until at least one byte of free space available
+ * or urgent Byte was consumed
+ */
+static int smc_tx_wait(struct smc_sock *smc, int flags)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct smc_connection *conn = &smc->conn;
@@ -103,14 +105,15 @@ static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
break;
}
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
- if (atomic_read(&conn->sndbuf_space))
- break; /* at least 1 byte of free space available */
+ if (atomic_read(&conn->sndbuf_space) && !conn->urg_tx_pend)
+ break; /* at least 1 byte of free & no urgent data */
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
sk_wait_event(sk, &timeo,
sk->sk_err ||
(sk->sk_shutdown & SEND_SHUTDOWN) ||
smc_cdc_rxed_any_close(conn) ||
- atomic_read(&conn->sndbuf_space),
+ (atomic_read(&conn->sndbuf_space) &&
+ !conn->urg_tx_pend),
&wait);
}
remove_wait_queue(sk_sleep(sk), &wait);
@@ -157,8 +160,11 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
if (smc_cdc_rxed_any_close(conn))
return send_done ?: -ECONNRESET;

- if (!atomic_read(&conn->sndbuf_space)) {
- rc = smc_tx_wait_memory(smc, msg->msg_flags);
+ if (msg->msg_flags & MSG_OOB)
+ conn->local_tx_ctrl.prod_flags.urg_data_pending = 1;
+
+ if (!atomic_read(&conn->sndbuf_space) || conn->urg_tx_pend) {
+ rc = smc_tx_wait(smc, msg->msg_flags);
if (rc) {
if (send_done)
return send_done;
@@ -168,7 +174,7 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
}

/* initialize variables for 1st iteration of subsequent loop */
- /* could be just 1 byte, even after smc_tx_wait_memory above */
+ /* could be just 1 byte, even after smc_tx_wait above */
writespace = atomic_read(&conn->sndbuf_space);
/* not more than what user space asked for */
copylen = min_t(size_t, send_remaining, writespace);
@@ -218,6 +224,8 @@ 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
*/
+ if ((msg->msg_flags & MSG_OOB) && !send_remaining)
+ conn->urg_tx_pend = true;
if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) &&
(atomic_read(&conn->sndbuf_space) >
(conn->sndbuf_desc->len >> 1)))
@@ -299,6 +307,7 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
union smc_host_cursor sent, prep, prod, cons;
struct ib_sge sges[SMC_IB_MAX_SEND_SGE];
struct smc_link_group *lgr = conn->lgr;
+ struct smc_cdc_producer_flags *pflags;
int to_send, rmbespace;
struct smc_link *link;
dma_addr_t dma_addr;
@@ -326,7 +335,8 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
conn);

/* if usable snd_wnd closes ask peer to advertise once it opens again */
- conn->local_tx_ctrl.prod_flags.write_blocked = (to_send >= rmbespace);
+ pflags = &conn->local_tx_ctrl.prod_flags;
+ pflags->write_blocked = (to_send >= rmbespace);
/* cf. usable snd_wnd */
len = min(to_send, rmbespace);

@@ -391,6 +401,8 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
src_len_sum = src_len;
}

+ if (conn->urg_tx_pend && len == to_send)
+ pflags->urg_data_present = 1;
smc_tx_advance_cursors(conn, &prod, &sent, len);
/* update connection's cursors with advanced local cursors */
smc_curs_write(&conn->local_tx_ctrl.prod,
@@ -410,6 +422,7 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
*/
int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
{
+ struct smc_cdc_producer_flags *pflags;
struct smc_cdc_tx_pend *pend;
struct smc_wr_buf *wr_buf;
int rc;
@@ -433,14 +446,21 @@ int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
goto out_unlock;
}

- rc = smc_tx_rdma_writes(conn);
- if (rc) {
- smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
- (struct smc_wr_tx_pend_priv *)pend);
- goto out_unlock;
+ if (!conn->local_tx_ctrl.prod_flags.urg_data_present) {
+ rc = smc_tx_rdma_writes(conn);
+ if (rc) {
+ smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
+ (struct smc_wr_tx_pend_priv *)pend);
+ goto out_unlock;
+ }
}

rc = smc_cdc_msg_send(conn, wr_buf, pend);
+ pflags = &conn->local_tx_ctrl.prod_flags;
+ if (!rc && pflags->urg_data_present) {
+ pflags->urg_data_pending = 0;
+ pflags->urg_data_present = 0;
+ }

out_unlock:
spin_unlock_bh(&conn->send_lock);
@@ -473,7 +493,7 @@ void smc_tx_work(struct work_struct *work)
release_sock(&smc->sk);
}

-void smc_tx_consumer_update(struct smc_connection *conn)
+void smc_tx_consumer_update(struct smc_connection *conn, bool force)
{
union smc_host_cursor cfed, cons;
int to_confirm;
@@ -487,6 +507,7 @@ void smc_tx_consumer_update(struct smc_connection *conn)
to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons);

if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
+ force ||
((to_confirm > conn->rmbe_update_limit) &&
((to_confirm > (conn->rmb_desc->len / 2)) ||
conn->local_rx_ctrl.prod_flags.write_blocked))) {
diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h
index 44d077942976..9d2238909fa0 100644
--- a/net/smc/smc_tx.h
+++ b/net/smc/smc_tx.h
@@ -32,6 +32,6 @@ 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);
void smc_tx_sndbuf_nonfull(struct smc_sock *smc);
-void smc_tx_consumer_update(struct smc_connection *conn);
+void smc_tx_consumer_update(struct smc_connection *conn, bool force);

#endif /* SMC_TX_H */
--
2.16.3