[PATCH v37 2/3] mm/page_poison: expose page_poisoning_enabled to kernel modules

From: Wei Wang <wei.w.wang@intel.com>
To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, mst@redhat.com, mhocko@kernel.org,
	akpm@linux-foundation.org, dgilbert@redhat.com
Cc: torvalds@linux-foundation.org, pbonzini@redhat.com,
	wei.w.wang@intel.com, liliang.opensource@gmail.com,
	yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com,
	riel@redhat.com, peterx@redhat.com, quintela@redhat.com
Subject: [PATCH v37 2/3] mm/page_poison: expose page_poisoning_enabled to kernel modules
Date: Mon, 27 Aug 2018 09:32:18 +0800	[thread overview]
Message-ID: <1535333539-32420-3-git-send-email-wei.w.wang@intel.com> (raw)
In-Reply-To: <1535333539-32420-1-git-send-email-wei.w.wang@intel.com>

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 <wei.w.wang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/page_poison.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/page_poison.c b/mm/page_poison.c
index aa2b3d3..830f604 100644
--- a/mm/page_poison.c
+++ b/mm/page_poison.c
@@ -17,6 +17,11 @@ static int __init early_page_poison_param(char *buf)
 }
 early_param("page_poison", early_page_poison_param);
 
+/**
+ * page_poisoning_enabled - check if page poisoning is enabled
+ *
+ * Return true if page poisoning is enabled, or false if not.
+ */
 bool page_poisoning_enabled(void)
 {
 	/*
@@ -29,6 +34,7 @@ bool page_poisoning_enabled(void)
 		(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
 		debug_pagealloc_enabled()));
 }
+EXPORT_SYMBOL_GPL(page_poisoning_enabled);
 
 static void poison_page(struct page *page)
 {
-- 
2.7.4

