[PATCH 1/5] ARM: dma-mapping: Treat bitmap size as allocation failure

[Yury Norov <ynorov@nvidia.com>]

bitmap_find_next_zero_area() uses an out-of-range return value to
indicate failure. Check for values greater than or equal to the bitmap
size so the caller does not depend on the exact failure sentinel.

Signed-off-by: Yury Norov <ynorov@nvidia.com>
---
 arch/arm/mm/dma-mapping.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f9bc53b60f99..7761099dde9e 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -773,7 +773,7 @@ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
 		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
 				mapping->bits, 0, count, align);
 
-		if (start > mapping->bits)
+		if (start >= mapping->bits)
 			continue;
 
 		bitmap_set(mapping->bitmaps[i], start, count);
@@ -794,7 +794,7 @@ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
 		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
 				mapping->bits, 0, count, align);
 
-		if (start > mapping->bits) {
+		if (start >= mapping->bits) {
 			spin_unlock_irqrestore(&mapping->lock, flags);
 			return DMA_MAPPING_ERROR;
 		}
-- 
2.53.0