Re: [PATCH -next v2] arm64/spinlock: fix a -Wunused-function warning

From: Will Deacon
Date: Mon Feb 03 2020 - 06:17:09 EST


On Thu, Jan 23, 2020 at 03:20:51PM -0500, Qian Cai wrote:
> The commit f5bfdc8e3947 ("locking/osq: Use optimized spinning loop for
> arm64") introduced a warning from Clang because vcpu_is_preempted() is
> compiled away,
>
> kernel/locking/osq_lock.c:25:19: warning: unused function 'node_cpu'
> [-Wunused-function]
> static inline int node_cpu(struct optimistic_spin_node *node)
> ^
> 1 warning generated.
>
> Fix it by converting vcpu_is_preempted() to a static inline function.
>
> Fixes: f5bfdc8e3947 ("locking/osq: Use optimized spinning loop for arm64")
> Signed-off-by: Qian Cai <cai@xxxxxx>
> ---
>
> v2: convert vcpu_is_preempted() to a static inline function.
>
> arch/arm64/include/asm/spinlock.h | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h
> index 102404dc1e13..9083d6992603 100644
> --- a/arch/arm64/include/asm/spinlock.h
> +++ b/arch/arm64/include/asm/spinlock.h
> @@ -18,6 +18,10 @@
> * See:
> * https://lore.kernel.org/lkml/20200110100612.GC2827@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> */
> -#define vcpu_is_preempted(cpu) false
> +#define vcpu_is_preempted vcpu_is_preempted
> +static inline bool vcpu_is_preempted(int cpu)
> +{
> + return false;
> +}

Cheers, I'll queue this at -rc1.

Will