smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES

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 <[e-mail]>
cc: Karsten Graul <[e-mail]>
cc: Wenjia Zhang <[e-mail]>
cc: Jan Karcher <[e-mail]>
cc: "D. Wythe" <[e-mail]>
cc: Tony Lu <[e-mail]>
cc: Wen Gu <[e-mail]>
cc: Jens Axboe <[e-mail]>
cc: Matthew Wilcox <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/smc/af_smc.c

···
 	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.
···
 	.sendmsg	= smc_sendmsg,
 	.recvmsg	= smc_recvmsg,
 	.mmap		= sock_no_mmap,
-	.sendpage	= smc_sendpage,
 	.splice_read	= smc_splice_read,
 };
 

net/smc/smc_stats.c

···
 			      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,

net/smc/smc_stats.h

···
 	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;

net/smc/smc_tx.c

···
 	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;
-
-	if (flags & MSG_SENDPAGE_NOTLAST)
-		msg.msg_flags |= MSG_MORE;
-
-	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 */

net/smc/smc_tx.h

···
 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);