2 files changed, 21 insertions, 22 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 17ebe0f89bf3..a78fb4ac2015 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -131,11 +131,21 @@ struct kmem_cache {
 
 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
 
+#ifdef CONFIG_ZONE_DMA
+#define SLUB_DMA __GFP_DMA
+/* Reserve extra caches for potential DMA use */
+#define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT - 6)
+#else
+/* Disable DMA functionality */
+#define SLUB_DMA (__force gfp_t)0
+#define KMALLOC_CACHES SLUB_PAGE_SHIFT
+#endif
+
 /*
  * We keep the general caches in an array of slab caches that are used for
  * 2^x bytes of allocations.
  */
-extern struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT];
+extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES];
 
 /*
  * Sorry that the following has to be that ugly but some versions of GCC
@@ -203,13 +213,6 @@ static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
         return &kmalloc_caches[index];
 }
 
-#ifdef CONFIG_ZONE_DMA
-#define SLUB_DMA __GFP_DMA
-#else
-/* Disable DMA functionality */
-#define SLUB_DMA (__force gfp_t)0
-#endif
-
 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 void *__kmalloc(size_t size, gfp_t flags);
 
diff --git a/mm/slub.c b/mm/slub.c
index d6c9ecf629d5..cdb7f0214af0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2092,7 +2092,7 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
 {
         int cpu;
 
-        if (s < kmalloc_caches + SLUB_PAGE_SHIFT && s >= kmalloc_caches)
+        if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
                 /*
                  * Boot time creation of the kmalloc array. Use static per cpu data
                  * since the per cpu allocator is not available yet.
@@ -2539,7 +2539,7 @@ EXPORT_SYMBOL(kmem_cache_destroy);
  *              Kmalloc subsystem
  *******************************************************************/
 
-struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT] __cacheline_aligned;
+struct kmem_cache kmalloc_caches[KMALLOC_CACHES] __cacheline_aligned;
 EXPORT_SYMBOL(kmalloc_caches);
 
 static int __init setup_slub_min_order(char *str)
@@ -2629,6 +2629,7 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
         char *text;
         size_t realsize;
         unsigned long slabflags;
+        int i;
 
         s = kmalloc_caches_dma[index];
         if (s)
@@ -2649,18 +2650,13 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
         text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
                          (unsigned int)realsize);
 
-        if (flags & __GFP_WAIT)
-                s = kmalloc(kmem_size, flags & ~SLUB_DMA);
-        else {
-                int i;
+        s = NULL;
+        for (i = 0; i < KMALLOC_CACHES; i++)
+                if (!kmalloc_caches[i].size)
+                        break;
 
-                s = NULL;
-                for (i = 0; i < SLUB_PAGE_SHIFT; i++)
-                        if (kmalloc_caches[i].size) {
-                                s = kmalloc_caches + i;
-                                break;
-                        }
-        }
+        BUG_ON(i >= KMALLOC_CACHES);
+        s = kmalloc_caches + i;
 
         /*
          * Must defer sysfs creation to a workqueue because we don't know
@@ -2674,7 +2670,7 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
 
         if (!s || !text || !kmem_cache_open(s, flags, text,
                         realsize, ARCH_KMALLOC_MINALIGN, slabflags, NULL)) {
-                kfree(s);
+                s->size = 0;
                 kfree(text);
                 goto unlock_out;
         }