diff mbox

[v2] xen: avoid type warning in xchg_xen_ulong

Message ID 20170608085323.2209174-1-arnd@arndb.de
State Accepted
Commit 9cc91f212111cdcbefa02dcdb7dd443f224bf52c
Headers show

Commit Message

Arnd Bergmann June 8, 2017, 8:53 a.m. UTC
The improved type-checking version of container_of() triggers a warning for
xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t
contains a signed value:

drivers/xen/events/events_2l.c: In function 'evtchn_2l_handle_events':
drivers/xen/events/events_2l.c:187:1020: error: call to '__compiletime_assert_187' declared with attribute error: pointer type mismatch in container_of()

This adds a cast to work around the warning.

Cc: Ian Abbott <abbotti@mev.co.uk>
Fixes: 85323a991d40 ("xen: arm: mandate EABI and use generic atomic operations.")
Fixes: daa2ac80834d ("kernel.h: handle pointers to arrays better in container_of()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
v2: found the correct warning message and updated the changelog
---
 arch/arm/include/asm/xen/events.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.9.0

Comments

Ian Abbott June 8, 2017, 11:36 a.m. UTC | #1
On 2017-06-08 09:53, Arnd Bergmann wrote:
> The improved type-checking version of container_of() triggers a warning for

> xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t

> contains a signed value:

>

> drivers/xen/events/events_2l.c: In function 'evtchn_2l_handle_events':

> drivers/xen/events/events_2l.c:187:1020: error: call to '__compiletime_assert_187' declared with attribute error: pointer type mismatch in container_of()

>

> This adds a cast to work around the warning.

>

> Cc: Ian Abbott <abbotti@mev.co.uk>

> Fixes: 85323a991d40 ("xen: arm: mandate EABI and use generic atomic operations.")

> Fixes: daa2ac80834d ("kernel.h: handle pointers to arrays better in container_of()")

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> ---

> v2: found the correct warning message and updated the changelog

> ---

>  arch/arm/include/asm/xen/events.h | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

>

> diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h

> index 71e473d05fcc..620dc75362e5 100644

> --- a/arch/arm/include/asm/xen/events.h

> +++ b/arch/arm/include/asm/xen/events.h

> @@ -16,7 +16,7 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)

>  	return raw_irqs_disabled_flags(regs->ARM_cpsr);

>  }

>

> -#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((ptr),	\

> +#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((long long*)(ptr),\

>  							    atomic64_t,	\

>  							    counter), (val))

>

>


Acked-by: Ian Abbott <abbotti@mev.co.uk>


-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@mev.co.uk> )=-
-=(                          Web: http://www.mev.co.uk/  )=-
Stefano Stabellini June 8, 2017, 6:12 p.m. UTC | #2
On Thu, 8 Jun 2017, Arnd Bergmann wrote:
> The improved type-checking version of container_of() triggers a warning for

> xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t

> contains a signed value:

> 

> drivers/xen/events/events_2l.c: In function 'evtchn_2l_handle_events':

> drivers/xen/events/events_2l.c:187:1020: error: call to '__compiletime_assert_187' declared with attribute error: pointer type mismatch in container_of()

> 

> This adds a cast to work around the warning.

> 

> Cc: Ian Abbott <abbotti@mev.co.uk>

> Fixes: 85323a991d40 ("xen: arm: mandate EABI and use generic atomic operations.")

> Fixes: daa2ac80834d ("kernel.h: handle pointers to arrays better in container_of()")

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>


Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


I'll queue it up on xentip for Linux 4.13.


> ---

> v2: found the correct warning message and updated the changelog

> ---

>  arch/arm/include/asm/xen/events.h | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h

> index 71e473d05fcc..620dc75362e5 100644

> --- a/arch/arm/include/asm/xen/events.h

> +++ b/arch/arm/include/asm/xen/events.h

> @@ -16,7 +16,7 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)

>  	return raw_irqs_disabled_flags(regs->ARM_cpsr);

>  }

>  

> -#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((ptr),	\

> +#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((long long*)(ptr),\

>  							    atomic64_t,	\

>  							    counter), (val))

>  

> -- 

> 2.9.0

>
diff mbox

Patch

diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
index 71e473d05fcc..620dc75362e5 100644
--- a/arch/arm/include/asm/xen/events.h
+++ b/arch/arm/include/asm/xen/events.h
@@ -16,7 +16,7 @@  static inline int xen_irqs_disabled(struct pt_regs *regs)
 	return raw_irqs_disabled_flags(regs->ARM_cpsr);
 }
 
-#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((ptr),	\
+#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((long long*)(ptr),\
 							    atomic64_t,	\
 							    counter), (val))