2020-01-23 20:28:11

by Qian Cai

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

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 <[email protected]>
---

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/[email protected]
*/
-#define vcpu_is_preempted(cpu) false
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(int cpu)
+{
+ return false;
+}

#endif /* __ASM_SPINLOCK_H */
--
2.21.0 (Apple Git-122.2)

2020-02-03 12:25:45

by Will Deacon

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

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 <[email protected]>
> ---
>
> 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/[email protected]
> */
> -#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