Commit 951ace99 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

kcm: Use splice_eof() to flush 



Allow splice to undo the effects of MSG_MORE after prematurely ending a
splice/sendfile due to getting an EOF condition (->splice_read() returned
0) after splice had called sendmsg() with MSG_MORE set when the user didn't
set MSG_MORE.

Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/


Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Tom Herbert <tom@herbertland.com>
cc: Tom Herbert <tom@quantonium.net>
cc: Cong Wang <cong.wang@bytedance.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c289a160

net/kcm/kcmsock.c

+15 −0
Original line number Diff line number Diff line
@@ -968,6 +968,19 @@ static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	return err;

}



static void kcm_splice_eof(struct socket *sock)

{

	struct sock *sk = sock->sk;

	struct kcm_sock *kcm = kcm_sk(sk);



	if (skb_queue_empty_lockless(&sk->sk_write_queue))

		return;



	lock_sock(sk);

	kcm_write_msgs(kcm);

	release_sock(sk);

}



static ssize_t kcm_sendpage(struct socket *sock, struct page *page,

			    int offset, size_t size, int flags)
@@ -1773,6 +1786,7 @@ static const struct proto_ops kcm_dgram_ops = { 
	.sendmsg =	kcm_sendmsg,

	.recvmsg =	kcm_recvmsg,

	.mmap =		sock_no_mmap,

	.splice_eof =	kcm_splice_eof,

	.sendpage =	kcm_sendpage,

};
@@ -1794,6 +1808,7 @@ static const struct proto_ops kcm_seqpacket_ops = { 
	.sendmsg =	kcm_sendmsg,

	.recvmsg =	kcm_recvmsg,

	.mmap =		sock_no_mmap,

	.splice_eof =	kcm_splice_eof,

	.sendpage =	kcm_sendpage,

	.splice_read =	kcm_splice_read,

};