From c729ed6f5be57b4d164dbbc415554c066e29306b Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 23 Jun 2023 23:54:59 +0100 Subject: net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() Use sendmsg() with MSG_SPLICE_PAGES rather than sendpage in skb_send_sock(). This causes pages to be spliced from the source iterator if possible. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Note that this could perhaps be improved to fill out a bvec array with all the frags and then make a single sendmsg call, possibly sticking the header on the front also. Signed-off-by: David Howells cc: Jens Axboe cc: Matthew Wilcox Link: https://lore.kernel.org/r/20230623225513.2732256-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski --- net/core/skbuff.c | 50 ++++++++++++++++++++++++++++---------------------- 1 file changed, 28 insertions(+), 22 deletions(-) (limited to 'net/core/skbuff.c') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fee2b1c105fe..6c5915efbc17 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2989,32 +2989,32 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset, } EXPORT_SYMBOL_GPL(skb_splice_bits); -static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg, - struct kvec *vec, size_t num, size_t size) +static int sendmsg_locked(struct sock *sk, struct msghdr *msg) { struct socket *sock = sk->sk_socket; + size_t size = msg_data_left(msg); if (!sock) return -EINVAL; - return kernel_sendmsg(sock, msg, vec, num, size); + + if (!sock->ops->sendmsg_locked) + return sock_no_sendmsg_locked(sk, msg, size); + + return sock->ops->sendmsg_locked(sk, msg, size); } -static int sendpage_unlocked(struct sock *sk, struct page *page, int offset, - size_t size, int flags) +static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg) { struct socket *sock = sk->sk_socket; if (!sock) return -EINVAL; - return kernel_sendpage(sock, page, offset, size, flags); + return sock_sendmsg(sock, msg); } -typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg, - struct kvec *vec, size_t num, size_t size); -typedef int (*sendpage_func)(struct sock *sk, struct page *page, int offset, - size_t size, int flags); +typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg); static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, - int len, sendmsg_func sendmsg, sendpage_func sendpage) + int len, sendmsg_func sendmsg) { unsigned int orig_len = len; struct sk_buff *head = skb; @@ -3034,8 +3034,9 @@ do_frag_list: memset(&msg, 0, sizeof(msg)); msg.msg_flags = MSG_DONTWAIT; - ret = INDIRECT_CALL_2(sendmsg, kernel_sendmsg_locked, - sendmsg_unlocked, sk, &msg, &kv, 1, slen); + iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen); + ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); if (ret <= 0) goto error; @@ -3066,11 +3067,18 @@ do_frag_list: slen = min_t(size_t, len, skb_frag_size(frag) - offset); while (slen) { - ret = INDIRECT_CALL_2(sendpage, kernel_sendpage_locked, - sendpage_unlocked, sk, - skb_frag_page(frag), - skb_frag_off(frag) + offset, - slen, MSG_DONTWAIT); + struct bio_vec bvec; + struct msghdr msg = { + .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT, + }; + + bvec_set_page(&bvec, skb_frag_page(frag), slen, + skb_frag_off(frag) + offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, + slen); + + ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); if (ret <= 0) goto error; @@ -3107,16 +3115,14 @@ error: int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset, int len) { - return __skb_send_sock(sk, skb, offset, len, kernel_sendmsg_locked, - kernel_sendpage_locked); + return __skb_send_sock(sk, skb, offset, len, sendmsg_locked); } EXPORT_SYMBOL_GPL(skb_send_sock_locked); /* Send skb data on a socket. Socket must be unlocked. */ int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len) { - return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked, - sendpage_unlocked); + return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked); } /** -- cgit