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From:   Kees Cook <keescook@chromium.org>
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     Kees Cook <keescook@chromium.org>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org,
        David Gow <davidgow@google.com>,
        Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
        Guenter Roeck <linux@roeck-us.net>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH 1/6] slab: Clean up SLOB vs kmalloc() definition
Date:   Tue,  1 Nov 2022 15:33:09 -0700
Message-Id: <20221101223321.1326815-1-keescook@chromium.org>
In-Reply-To: <20221101222520.never.109-kees@kernel.org>
References: <20221101222520.never.109-kees@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

As already done for kmalloc_node(), clean up the #ifdef usage in the
definition of kmalloc() so that the SLOB-only version is an entirely
separate and much more readable function.

Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/slab.h | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 90877fcde70b..e08fe7978b5c 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -559,15 +559,15 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_align
  *	Try really hard to succeed the allocation but fail
  *	eventually.
  */
+#ifndef CONFIG_SLOB
 static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
 {
 	if (__builtin_constant_p(size)) {
-#ifndef CONFIG_SLOB
 		unsigned int index;
-#endif
+
 		if (size > KMALLOC_MAX_CACHE_SIZE)
 			return kmalloc_large(size, flags);
-#ifndef CONFIG_SLOB
+
 		index = kmalloc_index(size);
 
 		if (!index)
@@ -576,10 +576,18 @@ static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
 		return kmalloc_trace(
 				kmalloc_caches[kmalloc_type(flags)][index],
 				flags, size);
-#endif
 	}
 	return __kmalloc(size, flags);
 }
+#else
+static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
+{
+	if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
+		return kmalloc_large(size, flags);
+
+	return __kmalloc(size, flags);
+}
+#endif
 
 #ifndef CONFIG_SLOB
 static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
-- 
2.34.1