Commit 8fea4e96 authored by Pekka Enberg's avatar Pekka Enberg Committed by Linus Torvalds
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[PATCH] slab: object to index mapping cleanup 



Clean up the object to index mapping that has been spread around mm/slab.c.

Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b50ec7d8

mm/slab.c

+23 −11
Original line number Diff line number Diff line
@@ -609,6 +609,18 @@ static inline struct slab *virt_to_slab(const void *obj) 
	return page_get_slab(page);

}



static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,

				 unsigned int idx)

{

	return slab->s_mem + cache->buffer_size * idx;

}



static inline unsigned int obj_to_index(struct kmem_cache *cache,

					struct slab *slab, void *obj)

{

	return (unsigned)(obj - slab->s_mem) / cache->buffer_size;

}



/* These are the default caches for kmalloc. Custom caches can have other sizes. */

struct cache_sizes malloc_sizes[] = {

#define CACHE(x) { .cs_size = (x) },
@@ -1568,18 +1580,18 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp) 
		 * exist:

		 */

		struct slab *slabp = virt_to_slab(objp);

		int objnr;

		unsigned int objnr;



		objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;

		objnr = obj_to_index(cachep, slabp, objp);

		if (objnr) {

			objp = slabp->s_mem + (objnr - 1) * cachep->buffer_size;

			objp = index_to_obj(cachep, slabp, objnr - 1);

			realobj = (char *)objp + obj_offset(cachep);

			printk(KERN_ERR "Prev obj: start=%p, len=%d\n",

			       realobj, size);

			print_objinfo(cachep, objp, 2);

		}

		if (objnr + 1 < cachep->num) {

			objp = slabp->s_mem + (objnr + 1) * cachep->buffer_size;

			objp = index_to_obj(cachep, slabp, objnr + 1);

			realobj = (char *)objp + obj_offset(cachep);

			printk(KERN_ERR "Next obj: start=%p, len=%d\n",

			       realobj, size);
@@ -1598,7 +1610,7 @@ static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp) 
{

	int i;

	for (i = 0; i < cachep->num; i++) {

		void *objp = slabp->s_mem + cachep->buffer_size * i;

		void *objp = index_to_obj(cachep, slabp, i);



		if (cachep->flags & SLAB_POISON) {

#ifdef CONFIG_DEBUG_PAGEALLOC
@@ -1631,7 +1643,7 @@ static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp) 
	if (cachep->dtor) {

		int i;

		for (i = 0; i < cachep->num; i++) {

			void *objp = slabp->s_mem + cachep->buffer_size * i;

			void *objp = index_to_obj(cachep, slabp, i);

			(cachep->dtor) (objp, cachep, 0);

		}

	}
@@ -2307,7 +2319,7 @@ static void cache_init_objs(struct kmem_cache *cachep, 
	int i;



	for (i = 0; i < cachep->num; i++) {

		void *objp = slabp->s_mem + cachep->buffer_size * i;

		void *objp = index_to_obj(cachep, slabp, i);

#if DEBUG

		/* need to poison the objs? */

		if (cachep->flags & SLAB_POISON)
@@ -2363,7 +2375,7 @@ static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) 


static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp, int nodeid)

{

	void *objp = slabp->s_mem + (slabp->free * cachep->buffer_size);

	void *objp = index_to_obj(cachep, slabp, slabp->free);

	kmem_bufctl_t next;



	slabp->inuse++;
@@ -2380,7 +2392,7 @@ static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp, int nod 
static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, void *objp,

			  int nodeid)

{

	unsigned int objnr = (unsigned)(objp-slabp->s_mem) / cachep->buffer_size;

	unsigned int objnr = obj_to_index(cachep, slabp, objp);



#if DEBUG

	/* Verify that the slab belongs to the intended node */
@@ -2565,10 +2577,10 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, 
	if (cachep->flags & SLAB_STORE_USER)

		*dbg_userword(cachep, objp) = caller;



	objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;

	objnr = obj_to_index(cachep, slabp, objp);



	BUG_ON(objnr >= cachep->num);

	BUG_ON(objp != slabp->s_mem + objnr * cachep->buffer_size);

	BUG_ON(objp != index_to_obj(cachep, slabp, objnr));



	if (cachep->flags & SLAB_DEBUG_INITIAL) {

		/* Need to call the slab's constructor so the