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kernel: kmem_ptr_validate considered harmful

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This is a nasty and error prone API. It is no longer used, remove it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This commit is contained in:
Nick Piggin
2011-01-07 17:49:17 +11:00
parent 786a5e15b6
commit ccd35fb9f4
5 changed files with 1 additions and 99 deletions
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32
mm/slab.c
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@@ -2781,7 +2781,7 @@ static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
/*
* Map pages beginning at addr to the given cache and slab. This is required
* for the slab allocator to be able to lookup the cache and slab of a
* virtual address for kfree, ksize, kmem_ptr_validate, and slab debugging.
* virtual address for kfree, ksize, and slab debugging.
*/
static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
void *addr)
@@ -3660,36 +3660,6 @@ void *kmem_cache_alloc_notrace(struct kmem_cache *cachep, gfp_t flags)
EXPORT_SYMBOL(kmem_cache_alloc_notrace);
#endif
/**
* kmem_ptr_validate - check if an untrusted pointer might be a slab entry.
* @cachep: the cache we're checking against
* @ptr: pointer to validate
*
* This verifies that the untrusted pointer looks sane;
* it is _not_ a guarantee that the pointer is actually
* part of the slab cache in question, but it at least
* validates that the pointer can be dereferenced and
* looks half-way sane.
*
* Currently only used for dentry validation.
*/
int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr)
{
unsigned long size = cachep->buffer_size;
struct page *page;
if (unlikely(!kern_ptr_validate(ptr, size)))
goto out;
page = virt_to_page(ptr);
if (unlikely(!PageSlab(page)))
goto out;
if (unlikely(page_get_cache(page) != cachep))
goto out;
return 1;
out:
return 0;
}
#ifdef CONFIG_NUMA
void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{