Current implementation of __iommu_dma_alloc_pages() keeps adding
__GFP_HIGHMEM to GFP flags regardless of whether other zone flags are
already included in the incoming flags. If __GFP_DMA or __GFP_DMA32 is
set at the same time as __GFP_HIGHMEM, the allocation fails due to
invalid zone flag combination.
Fix this by checking for __GFP_DMA and __GFP_DMA32 in incoming GFP flags
and adding __GFP_HIGHMEM only if they are not present.
Signed-off-by: Tomasz Figa <tf...@chromium.org>
---
drivers/iommu/dma-iommu.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
Changes from v1:
- Update the comment as per Robin's suggestion.
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 9d1cebe7f6cb..bf23989b5158 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -445,8 +445,14 @@ static struct page **__iommu_dma_alloc_pages(unsigned int
count,
if (!pages)
return NULL;
- /* IOMMU can map any pages, so himem can also be used here */
- gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
+ /*
+ * Unless we have some addressing limitation implied by GFP_DMA flags,
+ * assume the IOMMU can map all of RAM and we can allocate anywhere.
+ */
+ if (!(gfp & (__GFP_DMA | __GFP_DMA32)))
+ gfp |= __GFP_HIGHMEM;
+
+ gfp |= __GFP_NOWARN;
while (count) {
struct page *page = NULL;
--
2.13.2.725.g09c95d1e9-goog
