On Fri, 18 Dec 2015 15:50:24 +0100
Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote:
> 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.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
> Cc: Sheng Yong <shengyong1@xxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: Zhu Guihua <zhugh.fnst@xxxxxxxxxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> Cc: Igor Mammedov <imammedo@xxxxxxxxxx>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> mm/memory_hotplug.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 67d488a..9392f01 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -127,11 +127,13 @@ void mem_hotplug_done(void)
> }
>
> /* add this memory to iomem resource */
> -static struct resource *register_memory_resource(u64 start, u64 size)
> +static int register_memory_resource(u64 start, u64 size,
> + struct resource **resource)
> {
> struct resource *res;
> res = kzalloc(sizeof(struct resource), GFP_KERNEL);
> - BUG_ON(!res);
> + if (!res)
> + return -ENOMEM;
>
> res->name = "System RAM";
> res->start = start;
> @@ -140,9 +142,10 @@ 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 -EEXIST;
> }
> - return res;
> + *resource = res;
> + return 0;
> }
>
> static void release_memory_resource(struct resource *res)
> @@ -1311,9 +1314,9 @@ int __ref add_memory(int nid, u64 start, u64 size)
> struct resource *res;
> int ret;
>
> - res = register_memory_resource(start, size);
> - if (!res)
> - return -EEXIST;
> + ret = register_memory_resource(start, size, &res);
> + if (ret)
> + return ret;
>
> ret = add_memory_resource(nid, res);
> if (ret < 0)
Reviewed-by: Igor Mammedov <imammedo@xxxxxxxxxx>
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