[PATCH] x86: DS cleanup - dont treat 0 as NULL

[PATCH] x86: DS cleanup - dont treat 0 as NULL

[Cyrill Gorcunov]

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Actually I wonder why in original code Atom processors was
_that_ aligned? Was it made with a special purpose? yes,
it's a mobile platform, but can't see any reason for such
alignment.

 arch/x86/kernel/ds.c |   18 +++++++++---------
 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c
index 5b32b6d..24a323c 100644
--- a/arch/x86/kernel/ds.c
+++ b/arch/x86/kernel/ds.c
@@ -238,12 +238,12 @@ static inline struct ds_context *ds_alloc_context(struct task_struct *task)
 		context = kzalloc(sizeof(*context), GFP_KERNEL);
 
 		if (!context)
-			return 0;
+			return NULL;
 
 		context->ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL);
 		if (!context->ds) {
 			kfree(context);
-			return 0;
+			return NULL;
 		}
 
 		*p_context = context;
@@ -279,7 +279,7 @@ static inline void ds_put_context(struct ds_context *context)
 	if (--context->count)
 		goto out;
 
-	*(context->this) = 0;
+	*(context->this) = NULL;
 
 	if (context->task)
 		clear_tsk_thread_flag(context->task, TIF_DS_AREA_MSR);
@@ -341,16 +341,16 @@ static inline void *ds_allocate_buffer(size_t size, unsigned int *pages)
 	rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
 	vm   = current->mm->total_vm  + pgsz;
 	if (rlim < vm)
-		return 0;
+		return NULL;
 
 	rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
 	vm   = current->mm->locked_vm  + pgsz;
 	if (rlim < vm)
-		return 0;
+		return NULL;
 
 	buffer = kzalloc(size, GFP_KERNEL);
 	if (!buffer)
-		return 0;
+		return NULL;
 
 	current->mm->total_vm  += pgsz;
 	current->mm->locked_vm += pgsz;
@@ -395,7 +395,7 @@ static int ds_request(struct task_struct *task, void *base, size_t size,
 	if (context->owner[qual] == current)
 		goto out_unlock;
 	error = -EPERM;
-	if (context->owner[qual] != 0)
+	if (context->owner[qual] != NULL)
 		goto out_unlock;
 	context->owner[qual] = current;
 
@@ -445,7 +445,7 @@ static int ds_request(struct task_struct *task, void *base, size_t size,
 	return error;
 
  out_release:
-	context->owner[qual] = 0;
+	context->owner[qual] = NULL;
 	ds_put_context(context);
 	return error;
 
@@ -825,7 +825,7 @@ void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
 			ds_configure(&ds_cfg_var);
 			break;
 		case 0xF: /* Core2 */
-        case 0x1C: /* Atom */
+		case 0x1C: /* Atom */
 			ds_configure(&ds_cfg_64);
 			break;
 		default:

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[H. Peter Anvin]

Cyrill Gorcunov wrote:
> 
> Actually I wonder why in original code Atom processors was
> _that_ aligned? Was it made with a special purpose? yes,
> it's a mobile platform, but can't see any reason for such
> alignment.
> 

I'm sorry, I don't see how this comment has anything to do with this patch?

	-hpa

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[H. Peter Anvin]

Cyrill Gorcunov wrote:
> 
> Actually I wonder why in original code Atom processors was
> _that_ aligned? Was it made with a special purpose? yes,
> it's a mobile platform, but can't see any reason for such
> alignment.
> 

[...]

> @@ -825,7 +825,7 @@ void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
>  			ds_configure(&ds_cfg_var);
>  			break;
>  		case 0xF: /* Core2 */
> -        case 0x1C: /* Atom */
> +		case 0x1C: /* Atom */
>  			ds_configure(&ds_cfg_64);
>  			break;
>  		default:
> 

Nevermind, I was looking for a *memory* alignment... :-/

	-hpa

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[Cyrill Gorcunov]

Oh, my fault, i had to be more concrete :(

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[Ingo Molnar]

* Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

thanks Cyrill, applied.

> @@ -825,7 +825,7 @@ void __cpuinit ds_init_intel(struct cpuinfo_x86 *c)
>  			ds_configure(&ds_cfg_var);
>  			break;
>  		case 0xF: /* Core2 */
> -        case 0x1C: /* Atom */
> +		case 0x1C: /* Atom */
>  			ds_configure(&ds_cfg_64);
>  			break;

to me it looks like a typo, not a sign of any real bug/thinko. The 
processor IDs there are a flat list.

	Ingo

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[David Newall]

Cyrill Gorcunov wrote:
> -			return 0;
> +			return NULL;

Why?  The constant 0 is C's official symbol for a null pointer.

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[H. Peter Anvin]

David Newall wrote:
> Cyrill Gorcunov wrote:
>> -			return 0;
>> +			return NULL;
> 
> Why?  The constant 0 is C's official symbol for a null pointer.

It's still bad style.

	-hpa

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[David Newall]

H. Peter Anvin wrote:
> David Newall wrote:
>> Cyrill Gorcunov wrote:
>>> -            return 0;
>>> +            return NULL;
>>
>> Why?  The constant 0 is C's official symbol for a null pointer.
>
> It's still bad style.

I disagree, but I don't want to debate the point.

Re: [PATCH] x86: DS cleanup - dont treat 0 as NULL

[Cyrill Gorcunov]

On Tue, Apr 29, 2008 at 10:23 AM, David Newall <davidn@davidnewall.com> wrote:
> Cyrill Gorcunov wrote:
>  > -                     return 0;
>  > +                     return NULL;
>
>  Why?  The constant 0 is C's official symbol for a null pointer.
>

Yes, but by using NULL explicilty allows you to separate _pointers_ from
numbers on review process. Or maybe you wanna drop NULL at all? I dont
think you will like that ;)