mm, slub: introduce kmem_cache_debug_flags() (59052e89) · Commits · 戴 / test

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:

Vlastimil Babka <vbabka@suse.cz> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Acked-by:

Roman Gushchin <guro@fb.com> Acked-by:

Christoph Lameter <cl@linux.com> Acked-by:

Kees 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:

Linus Torvalds <torvalds@linux-foundation.org>

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);

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