[PATCH 5.15 064/356] mm/cma: drop incorrect alignment check in cma_init_reserved_mem

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5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Frank van der Linden <fvdl@xxxxxxxxxx>

[ Upstream commit b174f139bdc8aaaf72f5b67ad1bd512c4868a87e ]

cma_init_reserved_mem uses IS_ALIGNED to check if the size represented by
one bit in the cma allocation bitmask is aligned with
CMA_MIN_ALIGNMENT_BYTES (pageblock size).

However, this is too strict, as this will fail if order_per_bit >
pageblock_order, which is a valid configuration.

We could check IS_ALIGNED both ways, but since both numbers are powers of
two, no check is needed at all.

Link: https://lkml.kernel.org/r/20240404162515.527802-1-fvdl@xxxxxxxxxx
Fixes: de9e14eebf33 ("drivers: dma-contiguous: add initialization from device tree")
Signed-off-by: Frank van der Linden <fvdl@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 mm/cma.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/cma.c b/mm/cma.c
index 5208aee4f45ad..88fbd4f8124d3 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -179,10 +179,6 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	if (!size || !memblock_is_region_reserved(base, size))
 		return -EINVAL;
 
-	/* alignment should be aligned with order_per_bit */
-	if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
-		return -EINVAL;
-
 	/* ensure minimal alignment required by mm core */
 	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
 		return -EINVAL;
-- 
2.43.0







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