* [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 12:46 ` Namhyung Kim
0 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 12:46 UTC (permalink / raw)
To: tj; +Cc: linux-kernel, kernel-janitors
percpu data has no special meaning in case of !CONFIG_SMP.
This removes lots of sparse warnings.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index a5a472b..8dfd41d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -15,7 +15,11 @@
# define __acquire(x) __context__(x,1)
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
-# define __percpu __attribute__((noderef, address_space(3)))
+# ifdef CONFIG_SMP
+# define __percpu __attribute__((noderef, address_space(3)))
+# else
+# define __percpu
+# endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else
--
1.7.0.4
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 12:46 ` Namhyung Kim
0 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 12:46 UTC (permalink / raw)
To: tj; +Cc: linux-kernel, kernel-janitors
percpu data has no special meaning in case of !CONFIG_SMP.
This removes lots of sparse warnings.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index a5a472b..8dfd41d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -15,7 +15,11 @@
# define __acquire(x) __context__(x,1)
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
-# define __percpu __attribute__((noderef, address_space(3)))
+# ifdef CONFIG_SMP
+# define __percpu __attribute__((noderef, address_space(3)))
+# else
+# define __percpu
+# endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else
--
1.7.0.4
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 12:46 ` Namhyung Kim
@ 2010-08-06 12:49 ` Tejun Heo
-1 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 12:49 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
On 08/06/2010 02:46 PM, Namhyung Kim wrote:
> percpu data has no special meaning in case of !CONFIG_SMP.
> This removes lots of sparse warnings.
>
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>
But they should still be accessed through the accessors and if they
are accessed through accessors, there shouldn't be sparse warnings
regarding them. Maybe UP accessors are missing proper markups? Do
those warnings only happen on UP config?
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 12:49 ` Tejun Heo
0 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 12:49 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
On 08/06/2010 02:46 PM, Namhyung Kim wrote:
> percpu data has no special meaning in case of !CONFIG_SMP.
> This removes lots of sparse warnings.
>
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>
But they should still be accessed through the accessors and if they
are accessed through accessors, there shouldn't be sparse warnings
regarding them. Maybe UP accessors are missing proper markups? Do
those warnings only happen on UP config?
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 12:49 ` Tejun Heo
@ 2010-08-06 12:53 ` Namhyung Kim
-1 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 12:53 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 14:49 +0200, Tejun Heo:
> On 08/06/2010 02:46 PM, Namhyung Kim wrote:
> > percpu data has no special meaning in case of !CONFIG_SMP.
> > This removes lots of sparse warnings.
> >
> > Signed-off-by: Namhyung Kim <namhyung@gmail.com>
>
> But they should still be accessed through the accessors and if they
> are accessed through accessors, there shouldn't be sparse warnings
> regarding them. Maybe UP accessors are missing proper markups? Do
> those warnings only happen on UP config?
>
They do nothing on UP.
quoting from include/asm-generic.h:
#else /* ! SMP */
#define per_cpu(var, cpu) (*((void)(cpu), &(var)))
#define __get_cpu_var(var) (var)
#define __raw_get_cpu_var(var) (var)
#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
#endif /* SMP */
--
Regards,
Namhyung Kim
--
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 12:53 ` Namhyung Kim
0 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 12:53 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 14:49 +0200, Tejun Heo:
> On 08/06/2010 02:46 PM, Namhyung Kim wrote:
> > percpu data has no special meaning in case of !CONFIG_SMP.
> > This removes lots of sparse warnings.
> >
> > Signed-off-by: Namhyung Kim <namhyung@gmail.com>
>
> But they should still be accessed through the accessors and if they
> are accessed through accessors, there shouldn't be sparse warnings
> regarding them. Maybe UP accessors are missing proper markups? Do
> those warnings only happen on UP config?
>
They do nothing on UP.
quoting from include/asm-generic.h:
#else /* ! SMP */
#define per_cpu(var, cpu) (*((void)(cpu), &(var)))
#define __get_cpu_var(var) (var)
#define __raw_get_cpu_var(var) (var)
#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
#endif /* SMP */
--
Regards,
Namhyung Kim
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 12:53 ` Namhyung Kim
@ 2010-08-06 12:57 ` Tejun Heo
-1 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 12:57 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
Hello,
On 08/06/2010 02:53 PM, Namhyung Kim wrote:
>> But they should still be accessed through the accessors and if they
>> are accessed through accessors, there shouldn't be sparse warnings
>> regarding them. Maybe UP accessors are missing proper markups? Do
>> those warnings only happen on UP config?
>>
>
> They do nothing on UP.
> quoting from include/asm-generic.h:
>
> #else /* ! SMP */
>
> #define per_cpu(var, cpu) (*((void)(cpu), &(var)))
> #define __get_cpu_var(var) (var)
> #define __raw_get_cpu_var(var) (var)
> #define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
> #define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
>
> #endif /* SMP */
Ah, I see. Then, the right thing to do is to add proper checking and
markups to UP accessors matching the SMP ones.
ie. __verify_pcpu_ptr() verification followed by __kernel __force
casting. Are you interested in doing it?
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 12:57 ` Tejun Heo
0 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 12:57 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
Hello,
On 08/06/2010 02:53 PM, Namhyung Kim wrote:
>> But they should still be accessed through the accessors and if they
>> are accessed through accessors, there shouldn't be sparse warnings
>> regarding them. Maybe UP accessors are missing proper markups? Do
>> those warnings only happen on UP config?
>>
>
> They do nothing on UP.
> quoting from include/asm-generic.h:
>
> #else /* ! SMP */
>
> #define per_cpu(var, cpu) (*((void)(cpu), &(var)))
> #define __get_cpu_var(var) (var)
> #define __raw_get_cpu_var(var) (var)
> #define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
> #define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
>
> #endif /* SMP */
Ah, I see. Then, the right thing to do is to add proper checking and
markups to UP accessors matching the SMP ones.
ie. __verify_pcpu_ptr() verification followed by __kernel __force
casting. Are you interested in doing it?
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 12:57 ` Tejun Heo
@ 2010-08-06 13:23 ` Namhyung Kim
-1 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 13:23 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 14:57 +0200, Tejun Heo:
> Ah, I see. Then, the right thing to do is to add proper checking and
> markups to UP accessors matching the SMP ones.
> ie. __verify_pcpu_ptr() verification followed by __kernel __force
> casting. Are you interested in doing it?
>
> Thanks.
>
Sure. :-)
Although I'm not sure that it is really needed, if so I'll do that.
--
Regards,
Namhyung Kim
--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@vger.kernel.org
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 13:23 ` Namhyung Kim
0 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 13:23 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 14:57 +0200, Tejun Heo:
> Ah, I see. Then, the right thing to do is to add proper checking and
> markups to UP accessors matching the SMP ones.
> ie. __verify_pcpu_ptr() verification followed by __kernel __force
> casting. Are you interested in doing it?
>
> Thanks.
>
Sure. :-)
Although I'm not sure that it is really needed, if so I'll do that.
--
Regards,
Namhyung Kim
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 13:23 ` Namhyung Kim
@ 2010-08-06 13:37 ` Tejun Heo
-1 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 13:37 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
Hello,
On 08/06/2010 03:23 PM, Namhyung Kim wrote:
> Sure. :-)
> Although I'm not sure that it is really needed, if so I'll do that.
Well, the whole __percpu markup thing is to detect misuse of percpu
pointers. I think it would definitely be better to have the sanity
check for UP code too. It's not like it's gonna cost any runtime
overhead and all the needed pieces are already there.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 13:37 ` Tejun Heo
0 siblings, 0 replies; 14+ messages in thread
From: Tejun Heo @ 2010-08-06 13:37 UTC (permalink / raw)
To: Namhyung Kim; +Cc: linux-kernel, kernel-janitors
Hello,
On 08/06/2010 03:23 PM, Namhyung Kim wrote:
> Sure. :-)
> Although I'm not sure that it is really needed, if so I'll do that.
Well, the whole __percpu markup thing is to detect misuse of percpu
pointers. I think it would definitely be better to have the sanity
check for UP code too. It's not like it's gonna cost any runtime
overhead and all the needed pieces are already there.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
2010-08-06 13:37 ` Tejun Heo
@ 2010-08-06 13:46 ` Namhyung Kim
-1 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 13:46 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 15:37 +0200, Tejun Heo:
> Hello,
>
Hi,
> On 08/06/2010 03:23 PM, Namhyung Kim wrote:
> > Sure. :-)
> > Although I'm not sure that it is really needed, if so I'll do that.
>
> Well, the whole __percpu markup thing is to detect misuse of percpu
> pointers. I think it would definitely be better to have the sanity
> check for UP code too. It's not like it's gonna cost any runtime
> overhead and all the needed pieces are already there.
>
> Thanks.
>
I see. Thanks for the comments.
--
Regards,
Namhyung Kim
--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] percpu: remove address_space attribute if !SMP
@ 2010-08-06 13:46 ` Namhyung Kim
0 siblings, 0 replies; 14+ messages in thread
From: Namhyung Kim @ 2010-08-06 13:46 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-kernel, kernel-janitors
2010-08-06 (금), 15:37 +0200, Tejun Heo:
> Hello,
>
Hi,
> On 08/06/2010 03:23 PM, Namhyung Kim wrote:
> > Sure. :-)
> > Although I'm not sure that it is really needed, if so I'll do that.
>
> Well, the whole __percpu markup thing is to detect misuse of percpu
> pointers. I think it would definitely be better to have the sanity
> check for UP code too. It's not like it's gonna cost any runtime
> overhead and all the needed pieces are already there.
>
> Thanks.
>
I see. Thanks for the comments.
--
Regards,
Namhyung Kim
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2010-08-06 13:46 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-08-06 12:46 [PATCH] percpu: remove address_space attribute if !SMP Namhyung Kim
2010-08-06 12:46 ` Namhyung Kim
2010-08-06 12:49 ` Tejun Heo
2010-08-06 12:49 ` Tejun Heo
2010-08-06 12:53 ` Namhyung Kim
2010-08-06 12:53 ` Namhyung Kim
2010-08-06 12:57 ` Tejun Heo
2010-08-06 12:57 ` Tejun Heo
2010-08-06 13:23 ` Namhyung Kim
2010-08-06 13:23 ` Namhyung Kim
2010-08-06 13:37 ` Tejun Heo
2010-08-06 13:37 ` Tejun Heo
2010-08-06 13:46 ` Namhyung Kim
2010-08-06 13:46 ` Namhyung Kim
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