From ebe73a284f4de8c5d401adeccd9b8fe3183b6e95 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Tue, 12 Jul 2022 21:52:30 +0100 Subject: [PATCH] net: Allow custom iter handler in msghdr Add support for custom iov_iter handling to msghdr. The idea is that in-kernel subsystems want control over how an SG is split. Signed-off-by: David Ahern [pavel: move callback into msghdr] Signed-off-by: Pavel Begunkov Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 7 ++++--- include/linux/socket.h | 4 ++++ net/core/datagram.c | 14 ++++++++++---- net/core/skbuff.c | 2 +- 4 files changed, 19 insertions(+), 8 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8e12b3b9ad6c..a8a2dd4cfdfd 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1776,13 +1776,14 @@ void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref); void msg_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg, bool success); -int __zerocopy_sg_from_iter(struct sock *sk, struct sk_buff *skb, - struct iov_iter *from, size_t length); +int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, + struct sk_buff *skb, struct iov_iter *from, + size_t length); static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len) { - return __zerocopy_sg_from_iter(skb->sk, skb, &msg->msg_iter, len); + return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len); } int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb, diff --git a/include/linux/socket.h b/include/linux/socket.h index 7bac9fc1cee0..3c11ef18a9cf 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -14,6 +14,8 @@ struct file; struct pid; struct cred; struct socket; +struct sock; +struct sk_buff; #define __sockaddr_check_size(size) \ BUILD_BUG_ON(((size) > sizeof(struct __kernel_sockaddr_storage))) @@ -70,6 +72,8 @@ struct msghdr { __kernel_size_t msg_controllen; /* ancillary data buffer length */ struct kiocb *msg_iocb; /* ptr to iocb for async requests */ struct ubuf_info *msg_ubuf; + int (*sg_from_iter)(struct sock *sk, struct sk_buff *skb, + struct iov_iter *from, size_t length); }; struct user_msghdr { diff --git a/net/core/datagram.c b/net/core/datagram.c index 50f4faeea76c..28cdb79df74d 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -613,10 +613,16 @@ fault: } EXPORT_SYMBOL(skb_copy_datagram_from_iter); -int __zerocopy_sg_from_iter(struct sock *sk, struct sk_buff *skb, - struct iov_iter *from, size_t length) +int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, + struct sk_buff *skb, struct iov_iter *from, + size_t length) { - int frag = skb_shinfo(skb)->nr_frags; + int frag; + + if (msg && msg->sg_from_iter) + return msg->sg_from_iter(sk, skb, from, length); + + frag = skb_shinfo(skb)->nr_frags; while (length && iov_iter_count(from)) { struct page *pages[MAX_SKB_FRAGS]; @@ -702,7 +708,7 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from) if (skb_copy_datagram_from_iter(skb, 0, from, copy)) return -EFAULT; - return __zerocopy_sg_from_iter(NULL, skb, from, ~0U); + return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U); } EXPORT_SYMBOL(zerocopy_sg_from_iter); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fc22b3d32052..f5a3ebbc1f7e 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1358,7 +1358,7 @@ int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb, if (orig_uarg && uarg != orig_uarg) return -EEXIST; - err = __zerocopy_sg_from_iter(sk, skb, &msg->msg_iter, len); + err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len); if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) { struct sock *save_sk = skb->sk; -- 2.11.0