iommu: fix MAX_ORDER usage in __iommu_dma_alloc_pages()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in __iommu_dma_alloc_pages().
Also use GENMASK() instead of hard to read "(2U << order) - 1" magic.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Robin Murphy <[email protected]>
Reviewed-by: Jacob Pan <[email protected]>
Acked-by: Joerg Roedel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 99b2646..ac996fd 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -736,7 +736,7 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
struct page **pages;
unsigned int i = 0, nid = dev_to_node(dev);
- order_mask &= (2U << MAX_ORDER) - 1;
+ order_mask &= GENMASK(MAX_ORDER - 1, 0);
if (!order_mask)
return NULL;
@@ -756,7 +756,7 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
* than a necessity, hence using __GFP_NORETRY until
* falling back to minimum-order allocations.
*/
- for (order_mask &= (2U << __fls(count)) - 1;
+ for (order_mask &= GENMASK(__fls(count), 0);
order_mask; order_mask &= ~order_size) {
unsigned int order = __fls(order_mask);
gfp_t alloc_flags = gfp;
