From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 049CC8D0047 for ; Thu, 10 Mar 2011 02:20:58 -0500 (EST) Message-ID: <4D787C30.1020407@cn.fujitsu.com> Date: Thu, 10 Mar 2011 15:22:24 +0800 From: Lai Jiangshan MIME-Version: 1.0 Subject: [PATCH 3/3 V2] slab,rcu: don't assume the size of struct rcu_head References: <4D6CA843.3090103@cn.fujitsu.com> In-Reply-To: <4D6CA843.3090103@cn.fujitsu.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Ingo Molnar , "Paul E. McKenney" , Christoph Lameter , Eric Dumazet , "David S. Miller" , Matt Mackall , linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org The size of struct rcu_head may be changed. When it becomes larger, it may pollute the data after struct slab. Signed-off-by: Lai Jiangshan --- diff --git a/mm/slab.c b/mm/slab.c index 37961d1..52cf0b4 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -191,22 +191,6 @@ typedef unsigned int kmem_bufctl_t; #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3) /* - * struct slab - * - * Manages the objs in a slab. Placed either at the beginning of mem allocated - * for a slab, or allocated from an general cache. - * Slabs are chained into three list: fully used, partial, fully free slabs. - */ -struct slab { - struct list_head list; - unsigned long colouroff; - void *s_mem; /* including colour offset */ - unsigned int inuse; /* num of objs active in slab */ - kmem_bufctl_t free; - unsigned short nodeid; -}; - -/* * struct slab_rcu * * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to @@ -219,8 +203,6 @@ struct slab { * * rcu_read_lock before reading the address, then rcu_read_unlock after * taking the spinlock within the structure expected at that address. - * - * We assume struct slab_rcu can overlay struct slab when destroying. */ struct slab_rcu { struct rcu_head head; @@ -229,6 +211,27 @@ struct slab_rcu { }; /* + * struct slab + * + * Manages the objs in a slab. Placed either at the beginning of mem allocated + * for a slab, or allocated from an general cache. + * Slabs are chained into three list: fully used, partial, fully free slabs. + */ +struct slab { + union { + struct { + struct list_head list; + unsigned long colouroff; + void *s_mem; /* including colour offset */ + unsigned int inuse; /* num of objs active in slab */ + kmem_bufctl_t free; + unsigned short nodeid; + }; + struct slab_rcu __slab_cover_slab_rcu; + }; +}; + +/* * struct array_cache * * Purpose: -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org