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slab,rcu: don't assume the size of struct rcu_head

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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 <cl@linux.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Lai Jiangshan 2011-03-10 15:22:24 +08:00 committed by Pekka Enberg
parent da9a638c6f
commit 5bfe53a77e
1 changed files with 21 additions and 18 deletions
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39
mm/slab.c
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@ -190,22 +190,6 @@ typedef unsigned int kmem_bufctl_t;
#define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2) #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3) #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 * struct slab_rcu
* *
@ -219,8 +203,6 @@ struct slab {
* *
* rcu_read_lock before reading the address, then rcu_read_unlock after * rcu_read_lock before reading the address, then rcu_read_unlock after
* taking the spinlock within the structure expected at that address. * 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 slab_rcu {
struct rcu_head head; struct rcu_head head;
@ -228,6 +210,27 @@ struct slab_rcu {
void *addr; 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 * struct array_cache
* *