From: Tejun Heo Subject: [PATCH percpu/for-3.15] percpu: allocation size should be even Date: Mon, 17 Mar 2014 16:12:01 -0400 Message-ID: <20140317201201.GD17373@mtj.dyndns.org> References: <20140305034751.GW18016@ZenIV.linux.org.uk> <20140305034919.GA26528@ZenIV.linux.org.uk> <20140306192026.GA14033@htj.dyndns.org> <20140306203030.GA18016@ZenIV.linux.org.uk> <20140306204726.GE14033@htj.dyndns.org> <20140307025206.GB18016@ZenIV.linux.org.uk> <20140314184545.GA29750@ZenIV.linux.org.uk> <20140314184745.GC6889@mtj.dyndns.org> <20140314185320.GO18016@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, Linus Torvalds , linux-kernel@vger.kernel.org, Stephen Tweedie , Jeremy Eder To: Al Viro Return-path: Content-Disposition: inline In-Reply-To: <20140314185320.GO18016@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org >From 2f69fa829cb4ca062aaffee9ab9eb44484db75b1 Mon Sep 17 00:00:00 2001 From: Viro 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 Signed-off-by: Tejun Heo --- 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