Messages in this thread Patch in this message | | | From | Weijie Yang <> | Subject | [PATCH] mm/cma: fix cma bitmap aligned mask computing | Date | Fri, 10 Oct 2014 10:15:53 +0800 |
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The current cma bitmap aligned mask compute way is incorrect, it could cause an unexpected align when using cma_alloc() if wanted align order is bigger than cma->order_per_bit.
Take kvm for example (PAGE_SHIFT = 12), kvm_cma->order_per_bit is set to 6, when kvm_alloc_rma() tries to alloc kvm_rma_pages, it will input 15 as expected align value, after using current computing, however, we get 0 as cma bitmap aligned mask other than 511.
This patch fixes the cma bitmap aligned mask compute way.
Signed-off-by: Weijie Yang <weijie.yang@samsung.com> --- mm/cma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/cma.c b/mm/cma.c index c17751c..f6207ef 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -57,7 +57,10 @@ unsigned long cma_get_size(struct cma *cma) static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) { - return (1UL << (align_order >> cma->order_per_bit)) - 1; + if (align_order <= cma->order_per_bit) + return 0; + else + return (1UL << (align_order - cma->order_per_bit)) - 1; } static unsigned long cma_bitmap_maxno(struct cma *cma) -- 1.7.10.4
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