[RFC PATCH v2 44/48] smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES

[David Howells <dhowells@redhat.com>]

Drop the smc_sendpage() code as smc_sendmsg() just passes the call down to
the underlying TCP socket and smc_tx_sendpage() is just a wrapper around
its sendmsg implementation.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Karsten Graul <kgraul@linux.ibm.com>
cc: Wenjia Zhang <wenjia@linux.ibm.com>
cc: Jan Karcher <jaka@linux.ibm.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-s390@vger.kernel.org
cc: netdev@vger.kernel.org
---
 net/smc/af_smc.c    | 29 -----------------------------
 net/smc/smc_stats.c |  2 +-
 net/smc/smc_stats.h |  1 -
 net/smc/smc_tx.c    | 16 ----------------
 net/smc/smc_tx.h    |  2 --
 5 files changed, 1 insertion(+), 49 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index a4cccdfdc00a..d4113c8a7cda 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -3125,34 +3125,6 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd,
 	return put_user(answ, (int __user *)arg);
 }
 
-static ssize_t smc_sendpage(struct socket *sock, struct page *page,
-			    int offset, size_t size, int flags)
-{
-	struct sock *sk = sock->sk;
-	struct smc_sock *smc;
-	int rc = -EPIPE;
-
-	smc = smc_sk(sk);
-	lock_sock(sk);
-	if (sk->sk_state != SMC_ACTIVE) {
-		release_sock(sk);
-		goto out;
-	}
-	release_sock(sk);
-	if (smc->use_fallback) {
-		rc = kernel_sendpage(smc->clcsock, page, offset,
-				     size, flags);
-	} else {
-		lock_sock(sk);
-		rc = smc_tx_sendpage(smc, page, offset, size, flags);
-		release_sock(sk);
-		SMC_STAT_INC(smc, sendpage_cnt);
-	}
-
-out:
-	return rc;
-}
-
 /* Map the affected portions of the rmbe into an spd, note the number of bytes
  * to splice in conn->splice_pending, and press 'go'. Delays consumer cursor
  * updates till whenever a respective page has been fully processed.
@@ -3224,7 +3196,6 @@ static const struct proto_ops smc_sock_ops = {
 	.sendmsg	= smc_sendmsg,
 	.recvmsg	= smc_recvmsg,
 	.mmap		= sock_no_mmap,
-	.sendpage	= smc_sendpage,
 	.splice_read	= smc_splice_read,
 };
 
diff --git a/net/smc/smc_stats.c b/net/smc/smc_stats.c
index e80e34f7ac15..ca14c0f3a07d 100644
--- a/net/smc/smc_stats.c
+++ b/net/smc/smc_stats.c
@@ -227,7 +227,7 @@ static int smc_nl_fill_stats_tech_data(struct sk_buff *skb,
 			      SMC_NLA_STATS_PAD))
 		goto errattr;
 	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_SENDPAGE_CNT,
-			      smc_tech->sendpage_cnt,
+			      0,
 			      SMC_NLA_STATS_PAD))
 		goto errattr;
 	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_CORK_CNT,
diff --git a/net/smc/smc_stats.h b/net/smc/smc_stats.h
index 84b7ecd8c05c..b60fe1eb37ab 100644
--- a/net/smc/smc_stats.h
+++ b/net/smc/smc_stats.h
@@ -71,7 +71,6 @@ struct smc_stats_tech {
 	u64			clnt_v2_succ_cnt;
 	u64			srv_v1_succ_cnt;
 	u64			srv_v2_succ_cnt;
-	u64			sendpage_cnt;
 	u64			urg_data_cnt;
 	u64			splice_cnt;
 	u64			cork_cnt;
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index f4b6a71ac488..d31ce8209fa2 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -298,22 +298,6 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
 	return rc;
 }
 
-int smc_tx_sendpage(struct smc_sock *smc, struct page *page, int offset,
-		    size_t size, int flags)
-{
-	struct msghdr msg = {.msg_flags = flags};
-	char *kaddr = kmap(page);
-	struct kvec iov;
-	int rc;
-
-	iov.iov_base = kaddr + offset;
-	iov.iov_len = size;
-	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, size);
-	rc = smc_tx_sendmsg(smc, &msg, size);
-	kunmap(page);
-	return rc;
-}
-
 /***************************** sndbuf consumer *******************************/
 
 /* sndbuf consumer: actual data transfer of one target chunk with ISM write */
diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h
index 34b578498b1f..a59f370b8b43 100644
--- a/net/smc/smc_tx.h
+++ b/net/smc/smc_tx.h
@@ -31,8 +31,6 @@ void smc_tx_pending(struct smc_connection *conn);
 void smc_tx_work(struct work_struct *work);
 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_sendpage(struct smc_sock *smc, struct page *page, int offset,
-		    size_t size, int flags);
 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, bool force);