Subject: [PATCH -mmotm 18/30] netvm: filter emergency skbs

From: Xiaotian Feng <[email-masked]>
Date: Tue, 13 Jul 2010 06:20:15 -0400

>>From b0240dd1e2ee0b4dc30f98c67cfe35e8c1833753 Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <[email-masked]>
Date: Tue, 13 Jul 2010 11:36:53 +0800
Subject: [PATCH 18/30] netvm: filter emergency skbs.

Toss all emergency packets not for a SOCK_MEMALLOC socket. This ensures our
precious memory reserve doesn't get stuck waiting for user-space.

The correctness of this approach relies on the fact that networks must be
assumed lossy.

Signed-off-by: Peter Zijlstra <[email-masked]>
Signed-off-by: Suresh Jayaraman <[email-masked]>
Signed-off-by: Xiaotian Feng <[email-masked]>
---
 net/core/filter.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 52b051f..bdcbc14 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -82,6 +82,9 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
 	int err;
 	struct sk_filter *filter;
 
+	if (skb_emergency(skb) && !sk_has_memalloc(sk))
+		return -ENOMEM;
+
 	err = security_sock_rcv_skb(sk, skb);
 	if (err)
 		return err;
-- 
1.7.1.1

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to [email-masked].  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"[email-masked]"> [email-masked] </a>