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Commit 5bfe53a7 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Pekka Enberg
Browse files

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: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent da9a638c

mm/slab.c

+21 −18
Original line number Diff line number Diff line
@@ -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

 *