3 files changed, 18 insertions, 4 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 9e7742f0a102..c704eed63c5d 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -183,6 +183,8 @@ static void *
 __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot)
 {
         struct arm_vmregion *c;
+        size_t align;
+        int bit;
 
         if (!consistent_pte[0]) {
                 printk(KERN_ERR "%s: not initialised\n", __func__);
@@ -191,9 +193,20 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot)
         }
 
         /*
+         * Align the virtual region allocation - maximum alignment is
+         * a section size, minimum is a page size.  This helps reduce
+         * fragmentation of the DMA space, and also prevents allocations
+         * smaller than a section from crossing a section boundary.
+         */
+        bit = fls(size - 1) + 1;
+        if (bit > SECTION_SHIFT)
+                bit = SECTION_SHIFT;
+        align = 1 << bit;
+
+        /*
          * Allocate a virtual address in the consistent mapping region.
          */
-        c = arm_vmregion_alloc(&consistent_head, size,
+        c = arm_vmregion_alloc(&consistent_head, align, size,
                             gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
         if (c) {
                 pte_t *pte;
diff --git a/arch/arm/mm/vmregion.c b/arch/arm/mm/vmregion.c
index 19e09bdb1b8a..935993e1b1ef 100644
--- a/arch/arm/mm/vmregion.c
+++ b/arch/arm/mm/vmregion.c
@@ -35,7 +35,8 @@
  */
 
 struct arm_vmregion *
-arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp)
+arm_vmregion_alloc(struct arm_vmregion_head *head, size_t align,
+                   size_t size, gfp_t gfp)
 {
         unsigned long addr = head->vm_start, end = head->vm_end - size;
         unsigned long flags;
@@ -58,7 +59,7 @@ arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp)
                         goto nospc;
                 if ((addr + size) <= c->vm_start)
                         goto found;
-                addr = c->vm_end;
+                addr = ALIGN(c->vm_end, align);
                 if (addr > end)
                         goto nospc;
         }
diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h
index 6b2cdbdf3a85..15e9f044db9f 100644
--- a/arch/arm/mm/vmregion.h
+++ b/arch/arm/mm/vmregion.h
@@ -21,7 +21,7 @@ struct arm_vmregion {
         int                     vm_active;
 };
 
-struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, gfp_t);
+struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, size_t, gfp_t);
 struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *, unsigned long);
 struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *, unsigned long);
 void arm_vmregion_free(struct arm_vmregion_head *, struct arm_vmregion *);