2 files changed, 26 insertions, 10 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 4dcbc2c71491..aa5d4a69d461 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -152,12 +152,10 @@ static __always_inline int kmalloc_index(size_t size)
         if (size <= KMALLOC_MIN_SIZE)
                 return KMALLOC_SHIFT_LOW;
 
-#if KMALLOC_MIN_SIZE <= 64
-        if (size > 64 && size <= 96)
+        if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
                 return 1;
-        if (size > 128 && size <= 192)
+        if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
                 return 2;
-#endif
         if (size <=          8) return 3;
         if (size <=         16) return 4;
         if (size <=         32) return 5;
diff --git a/mm/slub.c b/mm/slub.c
index e16c9fb1f48b..be493bd63c31 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2825,6 +2825,11 @@ static s8 size_index[24] = {
         2       /* 192 */
 };
 
+static inline int size_index_elem(size_t bytes)
+{
+        return (bytes - 1) / 8;
+}
+
 static struct kmem_cache *get_slab(size_t size, gfp_t flags)
 {
         int index;
@@ -2833,7 +2838,7 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags)
                 if (!size)
                         return ZERO_SIZE_PTR;
 
-                index = size_index[(size - 1) / 8];
+                index = size_index[size_index_elem(size)];
         } else
                 index = fls(size - 1);
 
@@ -3188,10 +3193,12 @@ void __init kmem_cache_init(void)
         slab_state = PARTIAL;
 
         /* Caches that are not of the two-to-the-power-of size */
-        if (KMALLOC_MIN_SIZE <= 64) {
+        if (KMALLOC_MIN_SIZE <= 32) {
                 create_kmalloc_cache(&kmalloc_caches[1],
                                 "kmalloc-96", 96, GFP_NOWAIT);
                 caches++;
+        }
+        if (KMALLOC_MIN_SIZE <= 64) {
                 create_kmalloc_cache(&kmalloc_caches[2],
                                 "kmalloc-192", 192, GFP_NOWAIT);
                 caches++;
@@ -3218,17 +3225,28 @@ void __init kmem_cache_init(void)
         BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
                 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
 
-        for (i = 8; i < KMALLOC_MIN_SIZE; i += 8)
-                size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW;
+        for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
+                int elem = size_index_elem(i);
+                if (elem >= ARRAY_SIZE(size_index))
+                        break;
+                size_index[elem] = KMALLOC_SHIFT_LOW;
+        }
 
-        if (KMALLOC_MIN_SIZE == 128) {
+        if (KMALLOC_MIN_SIZE == 64) {
+                /*
+                 * The 96 byte size cache is not used if the alignment
+                 * is 64 byte.
+                 */
+                for (i = 64 + 8; i <= 96; i += 8)
+                        size_index[size_index_elem(i)] = 7;
+        } else if (KMALLOC_MIN_SIZE == 128) {
                 /*
                  * The 192 byte sized cache is not used if the alignment
                  * is 128 byte. Redirect kmalloc to use the 256 byte cache
                  * instead.
                  */
                 for (i = 128 + 8; i <= 192; i += 8)
-                        size_index[(i - 1) / 8] = 8;
+                        size_index[size_index_elem(i)] = 8;
         }
 
         slab_state = UP;