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percpu: allocation size should be even

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723ad1d90b ("percpu: store offsets instead of lengths in ->map[]")
updated percpu area allocator to use the lowest bit, instead of sign,
to signify whether the area is occupied and forced min align to 2;
unfortunately, it forgot to force the allocation size to be even
causing malfunctions for the very rare odd-sized allocations.

Always force the allocations to be even sized.

tj: Wrote patch description.

Original-patch-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Viro
2014-03-17 16:01:27 -04:00
committed by Tejun Heo
parent 3d331ad74f
commit 2f69fa829c
1 changed files with 4 additions and 1 deletions
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5
mm/percpu.c
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@@ -713,11 +713,14 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
/* /*
* We want the lowest bit of offset available for in-use/free * We want the lowest bit of offset available for in-use/free
* indicator. * indicator, so force >= 16bit alignment and make size even.
*/ */
if (unlikely(align < 2)) if (unlikely(align < 2))
align = 2; align = 2;
if (unlikely(size & 1))
size++;
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
WARN(true, "illegal size (%zu) or align (%zu) for " WARN(true, "illegal size (%zu) or align (%zu) for "
"percpu allocation\n", size, align); "percpu allocation\n", size, align);