2021-02-21 13:47:54

by Shuo Liu

Subject: [PATCH RESEND v2 1/2] cpu/hotplug: Fix build error of using {add,remove}_cpu() with !CONFIG_SMP

From: Shuo Liu <[email protected]>

279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to
control vCPU") introduced {add,remove}_cpu() usage and it hit below
error with !CONFIG_SMP:

../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’:
../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration]
remove_cpu(cpu);

../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration]
add_cpu(cpu);

Add add_cpu() function prototypes with !CONFIG_SMP and remove_cpu() with
!CONFIG_HOTPLUG_CPU for such usage.

Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU")
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Shuo Liu <[email protected]>
Acked-by: Randy Dunlap <[email protected]> # build-tested
Cc: Stephen Rothwell <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Qais Yousef <[email protected]>
---
include/linux/cpu.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 3aaa0687e8df..94a578a96202 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -108,6 +108,8 @@ static inline void cpu_maps_update_done(void)
{
}

+static inline int add_cpu(unsigned int cpu) { return 0;}
+
#endif /* CONFIG_SMP */
extern struct bus_type cpu_subsys;

@@ -137,6 +139,7 @@ static inline int cpus_read_trylock(void) { return true; }
static inline void lockdep_assert_cpus_held(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
+static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
#endif /* !CONFIG_HOTPLUG_CPU */


base-commit: abaf6f60176f1ae9d946d63e4db63164600b7b1a
--
2.28.0

2021-02-23 15:14:26

by Qais Yousef

Subject: Re: [PATCH RESEND v2 1/2] cpu/hotplug: Fix build error of using {add,remove}_cpu() with !CONFIG_SMP

On 02/21/21 21:43, [email protected] wrote:
> From: Shuo Liu <[email protected]>
>
> 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to
> control vCPU") introduced {add,remove}_cpu() usage and it hit below
> error with !CONFIG_SMP:
>
> ../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’:
> ../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration]
> remove_cpu(cpu);
>
> ../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration]
> add_cpu(cpu);
>
> Add add_cpu() function prototypes with !CONFIG_SMP and remove_cpu() with
> !CONFIG_HOTPLUG_CPU for such usage.
>
> Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU")
> Reported-by: Randy Dunlap <[email protected]>
> Signed-off-by: Shuo Liu <[email protected]>
> Acked-by: Randy Dunlap <[email protected]> # build-tested
> Cc: Stephen Rothwell <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Qais Yousef <[email protected]>
> ---

Reviewed-by: Qais Yousef <[email protected]>

Thanks!

--
Qais Yousef

> include/linux/cpu.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/cpu.h b/include/linux/cpu.h
> index 3aaa0687e8df..94a578a96202 100644
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -108,6 +108,8 @@ static inline void cpu_maps_update_done(void)
> {
> }
>
> +static inline int add_cpu(unsigned int cpu) { return 0;}
> +
> #endif /* CONFIG_SMP */
> extern struct bus_type cpu_subsys;
>
> @@ -137,6 +139,7 @@ static inline int cpus_read_trylock(void) { return true; }
> static inline void lockdep_assert_cpus_held(void) { }
> static inline void cpu_hotplug_disable(void) { }
> static inline void cpu_hotplug_enable(void) { }
> +static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
> static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
> #endif /* !CONFIG_HOTPLUG_CPU */
>
>
> base-commit: abaf6f60176f1ae9d946d63e4db63164600b7b1a
> --
> 2.28.0
>