[PATCH 5.19 268/717] skmsg: Schedule psock work if the cached skb exists on the psock

Greg Kroah-Hartman
2022-10-22T08:03:10Z

From: Liu Jian <liujian56@huawei.com>

[ Upstream commit bec217197b412d74168c6a42fc0f76d0cc9cad00 ]

In sk_psock_backlog function, for ingress direction skb, if no new data
packet arrives after the skb is cached, the cached skb does not have a
chance to be added to the receive queue of psock. As a result, the cached
skb cannot be received by the upper-layer application. Fix this by reschedule
the psock work to dispose the cached skb in sk_msg_recvmsg function.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220907071311.60534-1-liujian56@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/skmsg.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 69ac686c7cae..864cd7ded2ca 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -435,8 +435,10 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
if (copied + copy > len)
copy = len - copied;
copy = copy_page_to_iter(page, sge->offset, copy, iter);
- if (!copy)
- return copied ? copied : -EFAULT;
+ if (!copy) {
+ copied = copied ? copied : -EFAULT;
+ goto out;
+ }

copied += copy;
if (likely(!peek)) {
@@ -456,7 +458,7 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
* didn't copy the entire length lets just break.
*/
if (copy != sge->length)
- return copied;
+ goto out;
sk_msg_iter_var_next(i);
}

@@ -478,7 +480,9 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
}
msg_rx = sk_psock_peek_msg(psock);
}
-
+out:
+ if (psock->work_state.skb && copied > 0)
+ schedule_work(&psock->work);
return copied;
}
EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
--
2.35.1