Commit 59052e89 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

mm, slub: introduce kmem_cache_debug_flags() 

There are few places that call kmem_cache_debug(s) (which tests if any of
debug flags are enabled for a cache) immediately followed by a test for a
specific flag.  The compiler can probably eliminate the extra check, but
we can make the code nicer by introducing kmem_cache_debug_flags() that
works like kmem_cache_debug() (including the static key check) but tests
for specific flag(s).  The next patches will add more users.

[vbabka@suse.cz: change return from int to bool, per Kees.  Add VM_WARN_ON_ONCE() for invalid flags, per Roman]
  Link: http://lkml.kernel.org/r/949b90ed-e0f0-07d7-4d21-e30ec0958a7c@suse.cz



Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-8-vbabka@suse.cz


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ca0cab65

mm/slub.c

+16 −5
Original line number Diff line number Diff line
@@ -122,18 +122,29 @@ DEFINE_STATIC_KEY_FALSE(slub_debug_enabled); 
#endif

#endif



static inline int kmem_cache_debug(struct kmem_cache *s)

/*

 * Returns true if any of the specified slub_debug flags is enabled for the

 * cache. Use only for flags parsed by setup_slub_debug() as it also enables

 * the static key.

 */

static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)

{

	VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));

#ifdef CONFIG_SLUB_DEBUG

	if (static_branch_unlikely(&slub_debug_enabled))

		return s->flags & SLAB_DEBUG_FLAGS;

		return s->flags & flags;

#endif

	return 0;

	return false;

}



static inline bool kmem_cache_debug(struct kmem_cache *s)

{

	return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);

}



void *fixup_red_left(struct kmem_cache *s, void *p)

{

	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)

	if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))

		p += s->red_left_pad;



	return p;
@@ -4060,7 +4071,7 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, 
	offset = (ptr - page_address(page)) % s->size;



	/* Adjust for redzone and reject if within the redzone. */

	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {

	if (kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {

		if (offset < s->red_left_pad)

			usercopy_abort("SLUB object in left red zone",

				       s->name, to_user, offset, n);