netdev - [PATCH v2 net-next 05/12] net: Clean up __sk_mem_raise

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Message-ID: <20250811173116.2829786-6-kuniyu@google.com>
Date: Mon, 11 Aug 2025 17:30:33 +0000
From: Kuniyuki Iwashima <kuniyu@...gle.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Neal Cardwell <ncardwell@...gle.com>, Paolo Abeni <pabeni@...hat.com>, 
	Willem de Bruijn <willemb@...gle.com>, Matthieu Baerts <matttbe@...nel.org>, 
	Mat Martineau <martineau@...nel.org>, Johannes Weiner <hannes@...xchg.org>, 
	Michal Hocko <mhocko@...nel.org>, Roman Gushchin <roman.gushchin@...ux.dev>, 
	Shakeel Butt <shakeel.butt@...ux.dev>, Andrew Morton <akpm@...ux-foundation.org>, 
	"Michal Koutný" <mkoutny@...e.com>, Tejun Heo <tj@...nel.org>
Cc: Simon Horman <horms@...nel.org>, Geliang Tang <geliang@...nel.org>, 
	Muchun Song <muchun.song@...ux.dev>, Mina Almasry <almasrymina@...gle.com>, 
	Kuniyuki Iwashima <kuniyu@...gle.com>, Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org, 
	mptcp@...ts.linux.dev, cgroups@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v2 net-next 05/12] net: Clean up __sk_mem_raise_allocated().

In __sk_mem_raise_allocated(), charged is initialised as true due
to the weird condition removed in the previous patch.

It makes the variable unreliable by itself, so we have to check
another variable, memcg, in advance.

Also, we will factorise the common check below for memcg later.

    if (mem_cgroup_sockets_enabled && sk->sk_memcg)

As a prep, let's initialise charged as false and memcg as NULL.

Signed-off-by: Kuniyuki Iwashima <kuniyu@...gle.com>
Reviewed-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/sock.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 380bc1aa6982..000940ecf360 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3263,15 +3263,16 @@ EXPORT_SYMBOL(sk_wait_data);
  */
 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
 {
-	struct mem_cgroup *memcg = mem_cgroup_sockets_enabled ? sk->sk_memcg : NULL;
 	struct proto *prot = sk->sk_prot;
-	bool charged = true;
+	struct mem_cgroup *memcg = NULL;
+	bool charged = false;
 	long allocated;
 
 	sk_memory_allocated_add(sk, amt);
 	allocated = sk_memory_allocated(sk);
 
-	if (memcg) {
+	if (mem_cgroup_sockets_enabled && sk->sk_memcg) {
+		memcg = sk->sk_memcg;
 		charged = mem_cgroup_charge_skmem(memcg, amt, gfp_memcg_charge());
 		if (!charged)
 			goto suppress_allocation;
@@ -3358,7 +3359,7 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
 
 	sk_memory_allocated_sub(sk, amt);
 
-	if (memcg && charged)
+	if (charged)
 		mem_cgroup_uncharge_skmem(memcg, amt);
 
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog