[PATCH 2/4] dmapool: Validate parameters to dma_pool_create

From: Matthew Wilcox
Date: Wed Sep 26 2007 - 15:01:46 EST


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@xxxxxxxxxxxxxxx>
---
mm/dmapool.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index a359b5e..f5d12a7 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -107,17 +107,18 @@ 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;
--
1.5.3.1

-
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