dmapool: Validate parameters to dma_pool_create

Check that 'align' is a power of two, like the API specifies.
Align 'size' to 'align' correctly -- the current code has an off-by-one.
The ALIGN macro in kernel.h doesn't.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 7 deletions

diff --git a/mm/dmapool.c b/mm/dmapool.c
index b5ff9ce8765b..744d541df866 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -106,17 +106,18 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 {
         struct dma_pool *retval;
 
-        if (align == 0)
+        if (align == 0) {
                 align = 1;
-        if (size == 0)
+        } else if (align & (align - 1)) {
                 return NULL;
-        else if (size < align)
-                size = align;
-        else if ((size % align) != 0) {
-                size += align + 1;
-                size &= ~(align - 1);
         }
 
+        if (size == 0)
+                return NULL;
+
+        if ((size % align) != 0)
+                size = ALIGN(size, align);
+
         if (allocation == 0) {
                 if (PAGE_SIZE < size)
                         allocation = size;