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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id w77sm513281pff.126.2020.06.17.10.56.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Jun 2020 10:56:43 -0700 (PDT) Date: Wed, 17 Jun 2020 10:56:42 -0700 From: Kees Cook To: Vlastimil Babka Cc: Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, vinmenon@codeaurora.org, Matthew Garrett , Roman Gushchin , Jann Horn , Vijayanand Jitta Subject: Re: [PATCH 7/9] mm, slub: introduce kmem_cache_debug_flags() Message-ID: <202006171055.64F6EB665@keescook> References: <20200610163135.17364-1-vbabka@suse.cz> <20200610163135.17364-8-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200610163135.17364-8-vbabka@suse.cz> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 10, 2020 at 06:31:33PM +0200, Vlastimil Babka wrote: > There are few places that call kmem_cache_debug(s) (which tests if any of debug > flags are enabled for a cache) immediatelly 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 specifig > flag(s). The next patches will add more users. > > Signed-off-by: Vlastimil Babka > --- > mm/slub.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 24d3e5f832aa..c8e8b4ae2451 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -122,18 +122,28 @@ 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 int kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags) This should return slab_flag_t, yes? > { > #ifdef CONFIG_SLUB_DEBUG > if (static_branch_unlikely(&slub_debug_enabled)) > - return s->flags & SLAB_DEBUG_FLAGS; > + return s->flags & flags; > #endif > return 0; > } > > +static inline int kmem_cache_debug(struct kmem_cache *s) And this too, as long as we're making changes here. -- Kees Cook