* [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu
@ 2012-12-07 5:40 Zhang Yanfei
2012-12-10 20:30 ` Marcelo Tosatti
2012-12-11 9:11 ` [PATCH] [RESEND] " Zhang Yanfei
0 siblings, 2 replies; 7+ messages in thread
From: Zhang Yanfei @ 2012-12-07 5:40 UTC (permalink / raw)
To: Eric W. Biederman, Gleb Natapov
Cc: kvm@vger.kernel.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org, kbuild test robot
This removes the sparse warning:
arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces)
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
arch/x86/include/asm/kexec.h | 4 +++-
arch/x86/kernel/crash.c | 4 ++--
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 28feeba..16882cd 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,7 +163,9 @@ struct kimage_arch {
};
#endif
-extern void (*crash_vmclear_loaded_vmcss)(void);
+extern void __rcu (*crash_vmclear_loaded_vmcss)(void);
+#define vmclear_func_rcu(vmclear_func) \
+ ((void (*)(void)) rcu_dereference(vmclear_func))
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 2f6b8e8..50ce1d6 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -38,7 +38,7 @@ int in_crash_kexec;
*
* protected by rcu.
*/
-void (*crash_vmclear_loaded_vmcss)(void) = NULL;
+void __rcu (*crash_vmclear_loaded_vmcss)(void) = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
static inline void cpu_crash_vmclear_loaded_vmcss(void)
@@ -46,7 +46,7 @@ static inline void cpu_crash_vmclear_loaded_vmcss(void)
void (*do_vmclear_operation)(void) = NULL;
rcu_read_lock();
- do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
+ do_vmclear_operation = vmclear_func_rcu(crash_vmclear_loaded_vmcss);
if (do_vmclear_operation)
do_vmclear_operation();
rcu_read_unlock();
--
1.7.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu
2012-12-07 5:40 [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu Zhang Yanfei
@ 2012-12-10 20:30 ` Marcelo Tosatti
2012-12-11 8:04 ` Zhang Yanfei
2012-12-11 9:11 ` [PATCH] [RESEND] " Zhang Yanfei
1 sibling, 1 reply; 7+ messages in thread
From: Marcelo Tosatti @ 2012-12-10 20:30 UTC (permalink / raw)
To: Zhang Yanfei
Cc: Eric W. Biederman, Gleb Natapov, kvm@vger.kernel.org,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
kbuild test robot
On Fri, Dec 07, 2012 at 01:40:56PM +0800, Zhang Yanfei wrote:
> This removes the sparse warning:
> arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces)
>
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
> arch/x86/include/asm/kexec.h | 4 +++-
> arch/x86/kernel/crash.c | 4 ++--
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 28feeba..16882cd 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -163,7 +163,9 @@ struct kimage_arch {
> };
> #endif
>
> -extern void (*crash_vmclear_loaded_vmcss)(void);
> +extern void __rcu (*crash_vmclear_loaded_vmcss)(void);
> +#define vmclear_func_rcu(vmclear_func) \
> + ((void (*)(void)) rcu_dereference(vmclear_func))
>
> #endif /* __ASSEMBLY__ */
>
> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
> index 2f6b8e8..50ce1d6 100644
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -38,7 +38,7 @@ int in_crash_kexec;
> *
> * protected by rcu.
> */
> -void (*crash_vmclear_loaded_vmcss)(void) = NULL;
> +void __rcu (*crash_vmclear_loaded_vmcss)(void) = NULL;
Isnt this (__rcu AS tag) sufficient? After all, sparse is complaining
about namespaces.
Creating a #define to cast seems excessive.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu
2012-12-10 20:30 ` Marcelo Tosatti
@ 2012-12-11 8:04 ` Zhang Yanfei
[not found] ` <50C6E927.9040605-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
0 siblings, 1 reply; 7+ messages in thread
From: Zhang Yanfei @ 2012-12-11 8:04 UTC (permalink / raw)
To: Marcelo Tosatti
Cc: Eric W. Biederman, Gleb Natapov, kvm@vger.kernel.org,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
kbuild test robot
于 2012年12月11日 04:30, Marcelo Tosatti 写道:
> On Fri, Dec 07, 2012 at 01:40:56PM +0800, Zhang Yanfei wrote:
>> This removes the sparse warning:
>> arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces)
>>
>> Reported-by: kbuild test robot <fengguang.wu@intel.com>
>> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
>> ---
>> arch/x86/include/asm/kexec.h | 4 +++-
>> arch/x86/kernel/crash.c | 4 ++--
>> 2 files changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 28feeba..16882cd 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -163,7 +163,9 @@ struct kimage_arch {
>> };
>> #endif
>>
>> -extern void (*crash_vmclear_loaded_vmcss)(void);
>> +extern void __rcu (*crash_vmclear_loaded_vmcss)(void);
>> +#define vmclear_func_rcu(vmclear_func) \
>> + ((void (*)(void)) rcu_dereference(vmclear_func))
>>
>> #endif /* __ASSEMBLY__ */
>>
>> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
>> index 2f6b8e8..50ce1d6 100644
>> --- a/arch/x86/kernel/crash.c
>> +++ b/arch/x86/kernel/crash.c
>> @@ -38,7 +38,7 @@ int in_crash_kexec;
>> *
>> * protected by rcu.
>> */
>> -void (*crash_vmclear_loaded_vmcss)(void) = NULL;
>> +void __rcu (*crash_vmclear_loaded_vmcss)(void) = NULL;
>
> Isnt this (__rcu AS tag) sufficient? After all, sparse is complaining
> about namespaces.
>
> Creating a #define to cast seems excessive.
>
>
I am not very familiar with the rcu.
Adding __rcu tag could solve the problem. But it imported another warning
when I try to assign rcu_dereference(crash_vmclear_loaded_vmcss) to
do_vmclear_operation:
arch/x86/kernel/crash.c:49:30: warning: incorrect type in assignment (different modifiers)
arch/x86/kernel/crash.c:49:30: expected void ( *do_vmclear_operation )( ... )
arch/x86/kernel/crash.c:49:30: got void ( [noderef] *<noident> )( ... )
arch/x86/kernel/crash.c:49:30: warning: incorrect type in assignment (different modifiers)
arch/x86/kernel/crash.c:49:30: expected void ( *do_vmclear_operation )( ... )
arch/x86/kernel/crash.c:49:30: got void ( [noderef] *<noident> )( ... )
So I made the #define to cast its type.
If you have any suggestion, that'll be helpful.
Thanks
Zhang Yanfei
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] [RESEND] x86/kexec: crash_vmclear_local_vmcss needs __rcu
2012-12-07 5:40 [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu Zhang Yanfei
2012-12-10 20:30 ` Marcelo Tosatti
@ 2012-12-11 9:11 ` Zhang Yanfei
[not found] ` <50C6F8C6.9000008-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
1 sibling, 1 reply; 7+ messages in thread
From: Zhang Yanfei @ 2012-12-11 9:11 UTC (permalink / raw)
To: Eric W. Biederman, Gleb Natapov
Cc: kvm@vger.kernel.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org, kbuild test robot
This removes the sparse warning:
arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces)
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
arch/x86/include/asm/kexec.h | 3 ++-
arch/x86/kernel/crash.c | 4 ++--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 28feeba..6080d26 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,7 +163,8 @@ struct kimage_arch {
};
#endif
-extern void (*crash_vmclear_loaded_vmcss)(void);
+typedef void crash_vmclear_fn(void);
+extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 2f6b8e8..74467fe 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -38,12 +38,12 @@ int in_crash_kexec;
*
* protected by rcu.
*/
-void (*crash_vmclear_loaded_vmcss)(void) = NULL;
+crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
static inline void cpu_crash_vmclear_loaded_vmcss(void)
{
- void (*do_vmclear_operation)(void) = NULL;
+ crash_vmclear_fn *do_vmclear_operation = NULL;
rcu_read_lock();
do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
--
1.7.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2012-12-11 21:55 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2012-12-07 5:40 [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu Zhang Yanfei
2012-12-10 20:30 ` Marcelo Tosatti
2012-12-11 8:04 ` Zhang Yanfei
[not found] ` <50C6E927.9040605-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-12-11 8:10 ` Gleb Natapov
2012-12-11 9:09 ` Zhang Yanfei
2012-12-11 9:11 ` [PATCH] [RESEND] " Zhang Yanfei
[not found] ` <50C6F8C6.9000008-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-12-11 21:55 ` Marcelo Tosatti
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