The patch titled
Subject: mm/cma: drop incorrect alignment check in cma_init_reserved_mem
has been added to the -mm mm-unstable branch. Its filename is
mm-cma-drop-incorrect-alignment-check-in-cma_init_reserved_mem.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-cma-drop-incorrect-alignment-check-in-cma_init_reserved_mem.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Frank van der Linden <fvdl@xxxxxxxxxx>
Subject: mm/cma: drop incorrect alignment check in cma_init_reserved_mem
Date: Thu, 4 Apr 2024 16:25:14 +0000
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>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/cma.c | 4 ----
1 file changed, 4 deletions(-)
--- a/mm/cma.c~mm-cma-drop-incorrect-alignment-check-in-cma_init_reserved_mem
+++ a/mm/cma.c
@@ -182,10 +182,6 @@ int __init cma_init_reserved_mem(phys_ad
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;
_
Patches currently in -mm which might be from fvdl@xxxxxxxxxx are
mm-cma-drop-incorrect-alignment-check-in-cma_init_reserved_mem.patch
mm-hugetlb-pass-correct-order_per_bit-to-cma_declare_contiguous_nid.patch
