linux-kernel - [PATCH v2 1/2] memory-hotplug: don't BUG() in register_memory

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Date:	Mon,  4 Jan 2016 17:17:30 +0100
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	linux-mm@...ck.org
Cc:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Rientjes <rientjes@...gle.com>,
	Tang Chen <tangchen@...fujitsu.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Xishi Qiu <qiuxishi@...wei.com>,
	Sheng Yong <shengyong1@...wei.com>,
	Zhu Guihua <zhugh.fnst@...fujitsu.com>,
	Dan Williams <dan.j.williams@...el.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Igor Mammedov <imammedo@...hat.com>
Subject: [PATCH v2 1/2] memory-hotplug: don't BUG() in register_memory_resource()

Out of memory condition is not a bug and while we can't add new memory in
such case crashing the system seems wrong. Propagating the return value
from register_memory_resource() requires interface change.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Tang Chen <tangchen@...fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc: Xishi Qiu <qiuxishi@...wei.com>
Cc: Sheng Yong <shengyong1@...wei.com>
Cc: Zhu Guihua <zhugh.fnst@...fujitsu.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: David Vrabel <david.vrabel@...rix.com>
Cc: Igor Mammedov <imammedo@...hat.com>
---
Changes since v1:
- Use ERR_PTR/PTR_ERR/IS_ERR() [David Rientjes]
---
 mm/memory_hotplug.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a042a9d..92f9595 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -131,7 +131,8 @@ static struct resource *register_memory_resource(u64 start, u64 size)
 {
 	struct resource *res;
 	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
-	BUG_ON(!res);
+	if (!res)
+		return ERR_PTR(-ENOMEM);
 
 	res->name = "System RAM";
 	res->start = start;
@@ -140,7 +141,7 @@ static struct resource *register_memory_resource(u64 start, u64 size)
 	if (request_resource(&iomem_resource, res) < 0) {
 		pr_debug("System RAM resource %pR cannot be added\n", res);
 		kfree(res);
-		res = NULL;
+		return ERR_PTR(-EEXIST);
 	}
 	return res;
 }
@@ -1312,8 +1313,8 @@ int __ref add_memory(int nid, u64 start, u64 size)
 	int ret;
 
 	res = register_memory_resource(start, size);
-	if (!res)
-		return -EEXIST;
+	if (IS_ERR(res))
+		return PTR_ERR(res);
 
 	ret = add_memory_resource(nid, res);
 	if (ret < 0)
-- 
2.4.3

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