Re: [PATCH] xen: remove incorrect forward declaration

From: Stefano Stabellini
Date: Mon May 16 2016 - 07:11:31 EST


On Wed, 11 May 2016, Arnd Bergmann wrote:
> A bugfix patch for the xen balloon driver introduced a forward
> declaration for a static function that is conditionally compiled,
> causing a warning if only the declaration but not the definition
> are there:
>
> drivers/xen/balloon.c:154:13: error: 'release_memory_resource' declared 'static' but never defined [-Werror=unused-function]
> static void release_memory_resource(struct resource *resource);
>
> This removes the declaration again and instead moves the function
> definition to the right place, before its first caller and inside
> of the #ifdef protecting both.
>
> The patch that introduced the warning is marked for stable
> backports, so if that gets applied to 4.4, so should this one.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Fixes: dfd74a1edfab ("xen/balloon: Fix crash when ballooning on x86 32 bit PAE")
> Cc: stable@xxxxxxxxxxxxxxx

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> drivers/xen/balloon.c | 28 +++++++++++++---------------
> 1 file changed, 13 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index d46839f51e73..e4db19e88ab1 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -151,8 +151,6 @@ static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
> static void balloon_process(struct work_struct *work);
> static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
>
> -static void release_memory_resource(struct resource *resource);
> -
> /* When ballooning out (allocating memory to return to Xen) we don't really
> want the kernel to try too hard since that can trigger the oom killer. */
> #define GFP_BALLOON \
> @@ -248,6 +246,19 @@ static enum bp_state update_schedule(enum bp_state state)
> }
>
> #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
> +static void release_memory_resource(struct resource *resource)
> +{
> + if (!resource)
> + return;
> +
> + /*
> + * No need to reset region to identity mapped since we now
> + * know that no I/O can be in this region
> + */
> + release_resource(resource);
> + kfree(resource);
> +}
> +
> static struct resource *additional_memory_resource(phys_addr_t size)
> {
> struct resource *res;
> @@ -286,19 +297,6 @@ static struct resource *additional_memory_resource(phys_addr_t size)
> return res;
> }
>
> -static void release_memory_resource(struct resource *resource)
> -{
> - if (!resource)
> - return;
> -
> - /*
> - * No need to reset region to identity mapped since we now
> - * know that no I/O can be in this region
> - */
> - release_resource(resource);
> - kfree(resource);
> -}
> -
> static enum bp_state reserve_additional_memory(void)
> {
> long credit;
> --
> 2.7.0
>