From: Paolo Abeni <pabeni@redhat.com>
Date: Thu, 30 Jun 2022 22:17:54 +0000 (-0700)
Subject: mptcp: never fetch fwd memory from the subflow
X-Git-Tag: v6.1-rc5~731^2~230^2~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4aaa1685f750b293316d2a09cde2ea25be2a5de2;p=platform%2Fkernel%2Flinux-starfive.git

mptcp: never fetch fwd memory from the subflow

The memory accounting is broken in such exceptional code
path, and after commit 4890b686f408 ("net: keep sk->sk_forward_alloc
as small as possible") we can't find much help there.

Drop the broken code.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 883bea9..9a6a4ab 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -328,15 +328,10 @@ static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
 
 	amt = sk_mem_pages(size);
 	amount = amt << PAGE_SHIFT;
-	msk->rmem_fwd_alloc += amount;
-	if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) {
-		if (ssk->sk_forward_alloc < amount) {
-			msk->rmem_fwd_alloc -= amount;
-			return false;
-		}
+	if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
+		return false;
 
-		ssk->sk_forward_alloc -= amount;
-	}
+	msk->rmem_fwd_alloc += amount;
 	return true;
 }