The CMA aligned offset calculation is incorrect for
non-zero order_per_bit values.
For example, if cma->order_per_bit=1, cma->base_pfn=
0x2f800000 and align_order=12, the function returns
a value of 0x17c00 instead of 0x400.
This patch fixes the CMA aligned offset calculation.
Cc: sta...@vger.kernel.org
Signed-off-by: Danesh Petigara <dpetig...@broadcom.com>
Reviewed-by: Gregory Fong <gregory.0...@gmail.com>
---
mm/cma.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/cma.c b/mm/cma.c
index 75016fd..58f37bd 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -70,9 +70,13 @@ static unsigned long cma_bitmap_aligned_offset(struct cma
*cma, int align_order)
if (align_order <= cma->order_per_bit)
return 0;
- alignment = 1UL << (align_order - cma->order_per_bit);
- return ALIGN(cma->base_pfn, alignment) -
- (cma->base_pfn >> cma->order_per_bit);
+
+ /*
+ * Find a PFN aligned to the specified order and return
+ * an offset represented in order_per_bits.
+ */
+ return (ALIGN(cma->base_pfn, (1UL << align_order))
+ - cma->base_pfn) >> cma->order_per_bit;
}
static unsigned long cma_bitmap_maxno(struct cma *cma)
--
1.9.1
--
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