From 59052e89fc89e3e6bef0151052e093566e446851 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 6 Aug 2020 23:18:55 -0700 Subject: [PATCH] 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: Vlastimil Babka Signed-off-by: Andrew Morton Acked-by: Roman Gushchin Acked-by: Christoph Lameter Acked-by: Kees Cook Cc: Jann Horn Cc: Vijayanand Jitta Cc: David Rientjes Cc: Joonsoo Kim Cc: Pekka Enberg Link: http://lkml.kernel.org/r/20200610163135.17364-8-vbabka@suse.cz Signed-off-by: Linus Torvalds --- mm/slub.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 8adab4c5296d..97074631a2d1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -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); -- 2.34.1