slab: Clean up SLOB vs kmalloc() definition

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>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 45efc6c..8a25d1b 100644 (file)
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -536,15 +536,15 @@ 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)
@@ -553,10 +553,18 @@ 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)