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| author | Weijie Yang <weijie.yang@samsung.com> | 2014-10-13 15:51:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-14 02:18:12 +0200 |
| commit | 68faed630fc151a7a1c4853df00fb3dcacf782b4 (patch) | |
| tree | d7381acab66692202b689195ee13230d83044dd6 /mm/cma.c | |
| parent | 85c9f4b04a08f6bc770b77530c22d04103468b8f (diff) | |
| download | lwn-68faed630fc151a7a1c4853df00fb3dcacf782b4.tar.gz lwn-68faed630fc151a7a1c4853df00fb3dcacf782b4.zip | |
mm/cma: fix cma bitmap aligned mask computing
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>
Cc: <stable@vger.kernel.org> [3.17]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/cma.c')
| -rw-r--r-- | mm/cma.c | 4 |
1 files changed, 3 insertions, 1 deletions
@@ -58,7 +58,9 @@ 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; + return (1UL << (align_order - cma->order_per_bit)) - 1; } static unsigned long cma_bitmap_maxno(struct cma *cma) |