>From 2f69fa829cb4ca062aaffee9ab9eb44484db75b1 Mon Sep 17 00:00:00 2001
From: Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Mon, 17 Mar 2014 16:01:27 -0400
723ad1d90b56 ("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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
Applied to percpu/for-3.15.
Thanks.
mm/percpu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/percpu.c b/mm/percpu.c
index c7206d0..202e104 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -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
- * indicator.
+ * indicator, so force >= 16bit alignment and make size even.
*/
if (unlikely(align < 2))
align = 2;
+ if (unlikely(size & 1))
+ size++;
+
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
WARN(true, "illegal size (%zu) or align (%zu) for "
"percpu allocation\n", size, align);
--
1.8.5.3
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