From: Stefan Raspl <stefan.raspl@linux.ibm.com>
Date: Thu, 3 May 2018 18:12:37 +0200
Subject: smc: make smc_rx_wait_data() generic
Patch-mainline: v4.18-rc1
Git-commit: b51fa1b135fbfc89e34d90b5bab563745d94186f
References: bsc#1096003, FATE#325023, LTC#164003

Turn smc_rx_wait_data into a generic function that can be used at various
instances to wait on traffic to complete with varying criteria.

Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com><
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 net/smc/af_smc.c |  2 +-
 net/smc/smc_rx.c | 21 +++++++++++----------
 net/smc/smc_rx.h |  8 +++++++-
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 95b00e4c3396..a7495c84ae15 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1089,7 +1089,7 @@ static int smc_accept(struct socket *sock, struct socket *new_sock,
 			release_sock(clcsk);
 		} else if (!atomic_read(&smc_sk(nsk)->conn.bytes_to_rcv)) {
 			lock_sock(nsk);
-			smc_rx_wait_data(smc_sk(nsk), &timeo);
+			smc_rx_wait(smc_sk(nsk), &timeo, smc_rx_data_available);
 			release_sock(nsk);
 		}
 	}
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index def33fb29ac9..7b64bee656e8 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -22,11 +22,10 @@
 #include "smc_tx.h" /* smc_tx_consumer_update() */
 #include "smc_rx.h"
 
-/* callback implementation for sk.sk_data_ready()
- * to wakeup rcvbuf consumers that blocked with smc_rx_wait_data().
+/* callback implementation to wakeup consumers blocked with smc_rx_wait().
  * indirectly called by smc_cdc_msg_recv_action().
  */
-static void smc_rx_data_ready(struct sock *sk)
+static void smc_rx_wake_up(struct sock *sk)
 {
 	struct socket_wq *wq;
 
@@ -47,25 +46,27 @@ static void smc_rx_data_ready(struct sock *sk)
 /* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted
  *   @smc    smc socket
  *   @timeo  pointer to max seconds to wait, pointer to value 0 for no timeout
+ *   @fcrit  add'l criterion to evaluate as function pointer
  * Returns:
  * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown.
  * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted).
  */
-int smc_rx_wait_data(struct smc_sock *smc, long *timeo)
+int smc_rx_wait(struct smc_sock *smc, long *timeo,
+		int (*fcrit)(struct smc_connection *conn))
 {
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	struct smc_connection *conn = &smc->conn;
 	struct sock *sk = &smc->sk;
 	int rc;
 
-	if (atomic_read(&conn->bytes_to_rcv))
+	if (fcrit(conn))
 		return 1;
 	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	add_wait_queue(sk_sleep(sk), &wait);
 	rc = sk_wait_event(sk, timeo,
 			   sk->sk_err ||
 			   sk->sk_shutdown & RCV_SHUTDOWN ||
-			   atomic_read(&conn->bytes_to_rcv) ||
+			   fcrit(conn) ||
 			   smc_cdc_rxed_any_close_or_senddone(conn),
 			   &wait);
 	remove_wait_queue(sk_sleep(sk), &wait);
@@ -146,14 +147,14 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
 				return -EAGAIN;
 		}
 
-		if (!atomic_read(&conn->bytes_to_rcv)) {
-			smc_rx_wait_data(smc, &timeo);
+		if (!smc_rx_data_available(conn)) {
+			smc_rx_wait(smc, &timeo, smc_rx_data_available);
 			continue;
 		}
 
 copy:
 		/* initialize variables for 1st iteration of subsequent loop */
-		/* could be just 1 byte, even after smc_rx_wait_data above */
+		/* could be just 1 byte, even after waiting on data above */
 		readable = atomic_read(&conn->bytes_to_rcv);
 		/* not more than what user space asked for */
 		copylen = min_t(size_t, read_remaining, readable);
@@ -213,5 +214,5 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
 /* Initialize receive properties on connection establishment. NB: not __init! */
 void smc_rx_init(struct smc_sock *smc)
 {
-	smc->sk.sk_data_ready = smc_rx_data_ready;
+	smc->sk.sk_data_ready = smc_rx_wake_up;
 }
diff --git a/net/smc/smc_rx.h b/net/smc/smc_rx.h
index 0b75a6b470e6..8f9f00997641 100644
--- a/net/smc/smc_rx.h
+++ b/net/smc/smc_rx.h
@@ -20,6 +20,12 @@
 void smc_rx_init(struct smc_sock *smc);
 int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, size_t len,
 		   int flags);
-int smc_rx_wait_data(struct smc_sock *smc, long *timeo);
+int smc_rx_wait(struct smc_sock *smc, long *timeo,
+		int (*fcrit)(struct smc_connection *conn));
+static inline int smc_rx_data_available(struct smc_connection *conn)
+{
+	return atomic_read(&conn->bytes_to_rcv);
+}
+
 
 #endif /* SMC_RX_H */