Commit 6e284c55 authored by Zhen Lei's avatar Zhen Lei Committed by Frederic Weisbecker
Browse files

mm: Remove kmem_valid_obj() 



Function kmem_dump_obj() will splat if passed a pointer to a non-slab
object. So nothing calls it directly, instead calling kmem_valid_obj()
first to determine whether the passed pointer to a valid slab object. This
means that merging kmem_valid_obj() into kmem_dump_obj() will make the
code more concise. Therefore, convert kmem_dump_obj() to work the same
way as vmalloc_dump_obj(), removing the need for the kmem_dump_obj()
caller to check kmem_valid_obj().  After this, there are no remaining
calls to kmem_valid_obj() anymore, and it can be safely removed.

Suggested-by: default avatarMatthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
parent b93c5fe1

include/linux/slab.h

+3 −2
Original line number Diff line number Diff line
@@ -245,8 +245,9 @@ DEFINE_FREE(kfree, void *, if (_T) kfree(_T)) 
size_t ksize(const void *objp);



#ifdef CONFIG_PRINTK

bool kmem_valid_obj(void *object);

void kmem_dump_obj(void *object);

bool kmem_dump_obj(void *object);

#else

static inline bool kmem_dump_obj(void *object) { return false; }

#endif



/*

mm/slab_common.c

+11 −30
Original line number Diff line number Diff line
@@ -528,26 +528,6 @@ bool slab_is_available(void) 
}



#ifdef CONFIG_PRINTK

/**

 * kmem_valid_obj - does the pointer reference a valid slab object?

 * @object: pointer to query.

 *

 * Return: %true if the pointer is to a not-yet-freed object from

 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer

 * is to an already-freed object, and %false otherwise.

 */

bool kmem_valid_obj(void *object)

{

	struct folio *folio;



	/* Some arches consider ZERO_SIZE_PTR to be a valid address. */

	if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))

		return false;

	folio = virt_to_folio(object);

	return folio_test_slab(folio);

}

EXPORT_SYMBOL_GPL(kmem_valid_obj);



static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)

{

	if (__kfence_obj_info(kpp, object, slab))
@@ -566,11 +546,11 @@ static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab * 
 * and, if available, the slab name, return address, and stack trace from

 * the allocation and last free path of that object.

 *

 * This function will splat if passed a pointer to a non-slab object.

 * If you are not sure what type of object you have, you should instead

 * use mem_dump_obj().

 * Return: %true if the pointer is to a not-yet-freed object from

 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer

 * is to an already-freed object, and %false otherwise.

 */

void kmem_dump_obj(void *object)

bool kmem_dump_obj(void *object)

{

	char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";

	int i;
@@ -578,13 +558,13 @@ void kmem_dump_obj(void *object) 
	unsigned long ptroffset;

	struct kmem_obj_info kp = { };



	if (WARN_ON_ONCE(!virt_addr_valid(object)))

		return;

	/* Some arches consider ZERO_SIZE_PTR to be a valid address. */

	if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))

		return false;

	slab = virt_to_slab(object);

	if (WARN_ON_ONCE(!slab)) {

		pr_cont(" non-slab memory.\n");

		return;

	}

	if (!slab)

		return false;



	kmem_obj_info(&kp, object, slab);

	if (kp.kp_slab_cache)

		pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
@@ -621,6 +601,7 @@ void kmem_dump_obj(void *object) 
		pr_info("    %pS\n", kp.kp_free_stack[i]);

	}



	return true;

}

EXPORT_SYMBOL_GPL(kmem_dump_obj);

#endif

mm/util.c

+1 −3
Original line number Diff line number Diff line
@@ -1060,10 +1060,8 @@ void mem_dump_obj(void *object) 
{

	const char *type;



	if (kmem_valid_obj(object)) {

		kmem_dump_obj(object);

	if (kmem_dump_obj(object))

		return;

	}



	if (vmalloc_dump_obj(object))

		return;