From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx202.postini.com [74.125.245.202]) by kanga.kvack.org (Postfix) with SMTP id 074366B004D for ; Mon, 30 Jan 2012 03:36:49 -0500 (EST) Received: by bkbzs2 with SMTP id zs2so2802545bkb.14 for ; Mon, 30 Jan 2012 00:36:48 -0800 (PST) From: Dmitry Antipov Subject: [PATCH 1/3] percpu: use ZERO_SIZE_PTR / ZERO_OR_NULL_PTR Date: Mon, 30 Jan 2012 12:37:34 +0400 Message-Id: <1327912654-8738-1-git-send-email-dmitry.antipov@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo , Christoph Lameter Cc: Rusty Russell , linux-mm@kvack.org, linux-kernel@vger.kernel.org, patches@linaro.org, linaro-dev@lists.linaro.org, Dmitry Antipov Fix pcpu_alloc() to return ZERO_SIZE_PTR if requested size is 0; fix free_percpu() to check passed pointer with ZERO_OR_NULL_PTR. Signed-off-by: Dmitry Antipov --- mm/percpu.c | 16 +++++++++++----- 1 files changed, 11 insertions(+), 5 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index f47af91..e903a19 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -702,7 +702,8 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success or NULL on failure. */ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) { @@ -713,7 +714,10 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) unsigned long flags; void __percpu *ptr; - if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { + if (unlikely(!size)) + return ZERO_SIZE_PTR; + + if (unlikely(size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { WARN(true, "illegal size (%zu) or align (%zu) for " "percpu allocation\n", size, align); return NULL; @@ -834,7 +838,8 @@ fail_unlock_mutex: * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success, NULL on failure. */ void __percpu *__alloc_percpu(size_t size, size_t align) { @@ -856,7 +861,8 @@ EXPORT_SYMBOL_GPL(__alloc_percpu); * Does GFP_KERNEL allocation. * * RETURNS: - * Percpu pointer to the allocated area on success, NULL on failure. + * ZERO_SIZE_PTR if @size is zero, percpu pointer to the + * allocated area on success or NULL on failure. */ void __percpu *__alloc_reserved_percpu(size_t size, size_t align) { @@ -917,7 +923,7 @@ void free_percpu(void __percpu *ptr) unsigned long flags; int off; - if (!ptr) + if (unlikely(ZERO_OR_NULL_PTR(ptr))) return; kmemleak_free_percpu(ptr); -- 1.7.7.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org