From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754157AbeBGSeX (ORCPT ); Wed, 7 Feb 2018 13:34:23 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753794AbeBGSeW (ORCPT ); Wed, 7 Feb 2018 13:34:22 -0500 Date: Wed, 7 Feb 2018 20:34:16 +0200 From: "Michael S. Tsirkin" To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, pbonzini@redhat.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com, huangzhichao@huawei.com Subject: Re: [PATCH v27 3/4] mm/page_poison: expose page_poisoning_enabled to kernel modules Message-ID: <20180207203004-mutt-send-email-mst@kernel.org> References: <1517986471-15185-1-git-send-email-wei.w.wang@intel.com> <1517986471-15185-4-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1517986471-15185-4-git-send-email-wei.w.wang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 07, 2018 at 02:54:30PM +0800, Wei Wang wrote: > In some usages, e.g. virtio-balloon, a kernel module needs to know if > page poisoning is in use. This patch exposes the page_poisoning_enabled > function to kernel modules. > > Signed-off-by: Wei Wang > Cc: Andrew Morton > Cc: Michal Hocko > Cc: Michael S. Tsirkin > --- > mm/page_poison.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/page_poison.c b/mm/page_poison.c > index e83fd44..c08d02a 100644 > --- a/mm/page_poison.c > +++ b/mm/page_poison.c > @@ -30,6 +30,11 @@ bool page_poisoning_enabled(void) > debug_pagealloc_enabled())); > } > > +/** > + * page_poisoning_enabled - check if page poisoning is enabled > + * > + * Return true if page poisoning is enabled, or false if not. > + */ > static void poison_page(struct page *page) > { > void *addr = kmap_atomic(page); > @@ -37,6 +42,7 @@ static void poison_page(struct page *page) > memset(addr, PAGE_POISON, PAGE_SIZE); > kunmap_atomic(addr); > } > +EXPORT_SYMBOL_GPL(page_poisoning_enabled); > > static void poison_pages(struct page *page, int n) > { Looks like both the comment and the export are in the wrong place. I'm a bit concerned that callers also in fact poke at the PAGE_POISON - exporting that seems to be more of an accident as it's only used without page_poisoning.c - it might be better to have page_poisoning_enabled get u8 * and set it. > -- > 2.7.4