From 951ace9951382a90a56e98590e0b9b651e7579b4 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 7 Jun 2023 19:19:15 +0100 Subject: [PATCH] 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: Linus Torvalds Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/ Signed-off-by: David Howells cc: Tom Herbert cc: Tom Herbert cc: Cong Wang cc: Jens Axboe cc: Matthew Wilcox Signed-off-by: Jakub Kicinski --- net/kcm/kcmsock.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index ba22af16b96d..7dee74430b59 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -968,6 +968,19 @@ out_error: 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, }; -- 2.25.1