6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Abeni <pabeni@xxxxxxxxxx>
commit 449e6912a2522af672e99992e1201a454910864e upstream.
If the recvmsg() blocks after receiving some data - i.e. due to
SO_RCVLOWAT - the MPTCP code will attempt multiple times to
adjust the receive buffer size, wrongly accounting every time the
cumulative of received data - instead of accounting only for the
delta.
Address the issue moving mptcp_rcv_space_adjust just after the
data reception and passing it only the just received bytes.
This also removes an unneeded difference between the TCP and MPTCP
RX code path implementation.
Fixes: 581302298524 ("mptcp: error out earlier on disconnect")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Link: https://patch.msgid.link/20241230-net-mptcp-rbuf-fixes-v1-1-8608af434ceb@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mptcp/protocol.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1939,6 +1939,8 @@ do_error:
goto out;
}
+static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied);
+
static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
struct msghdr *msg,
size_t len, int flags,
@@ -1992,6 +1994,7 @@ static int __mptcp_recvmsg_mskq(struct m
break;
}
+ mptcp_rcv_space_adjust(msk, copied);
return copied;
}
@@ -2268,7 +2271,6 @@ static int mptcp_recvmsg(struct sock *sk
}
pr_debug("block timeout %ld\n", timeo);
- mptcp_rcv_space_adjust(msk, copied);
err = sk_wait_data(sk, &timeo, NULL);
if (err < 0) {
err = copied ? : err;
@@ -2276,8 +2278,6 @@ static int mptcp_recvmsg(struct sock *sk
}
}
- mptcp_rcv_space_adjust(msk, copied);
-
out_err:
if (cmsg_flags && copied >= 0) {
if (cmsg_flags & MPTCP_CMSG_TS)
