Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.17 108/146] mm/cma: fix cma bitmap aligned mask computing | Date | Tue, 28 Oct 2014 11:34:10 +0800 |
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3.17-stable review patch. If anyone has any objections, please let me know.
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From: Weijie Yang <weijie.yang@samsung.com>
commit 68faed630fc151a7a1c4853df00fb3dcacf782b4 upstream.
The current cma bitmap aligned mask computation is incorrect. It could cause an unexpected alignment when using cma_alloc() if the wanted align order is larger 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 use 15 as the expected align value. After using the current implementation however, we get 0 as cma bitmap aligned mask other than 511.
This patch fixes the cma bitmap aligned mask calculation.
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/cma.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/cma.c +++ b/mm/cma.c @@ -57,7 +57,9 @@ unsigned long cma_get_size(struct cma *c 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; + return (1UL << (align_order - cma->order_per_bit)) - 1; } static unsigned long cma_bitmap_maxno(struct cma *cma)
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