From 5bfe53a77e8a3ffce4a10003c75f464a138e272d Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 10 Mar 2011 15:22:24 +0800 Subject: slab,rcu: don't assume the size of struct rcu_head The size of struct rcu_head may be changed. When it becomes larger, it may pollute the data after struct slab. Acked-by: Christoph Lameter Signed-off-by: Lai Jiangshan Signed-off-by: Pekka Enberg --- mm/slab.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) (limited to 'mm/slab.c') diff --git a/mm/slab.c b/mm/slab.c index 37961d1f584f..52cf0b4634d4 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -190,22 +190,6 @@ typedef unsigned int kmem_bufctl_t; #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2) #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 * @@ -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; @@ -228,6 +210,27 @@ struct slab_rcu { void *addr; }; +/* + * 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 * -- cgit v1.2.3