Re: [PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-10 Thread Chen Gang 
On 10/10/2013 05:58 PM, Will Deacon wrote:
> On Thu, Oct 10, 2013 at 03:34:02AM +0100, Chen Gang wrote:
>> In current kernel wide source, for arm, only s390 scsi drivers use
>> atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
>> 'atomic_t', so need match s390's atomic_clear_mask().
>>
>>
>> Signed-off-by: Chen Gang 
>> ---
>>  arch/arm/include/asm/atomic.h |   13 +++--
>>  1 files changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
>> index da1c77d..0832a7f 100644
>> --- a/arch/arm/include/asm/atomic.h
>> +++ b/arch/arm/include/asm/atomic.h
>> @@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int 
>> old, int new)
>>  return oldval;
>>  }
>>  
>> -static inline void atomic_clear_mask(unsigned long mask, unsigned long 
>> *addr)
>> +static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
>>  {
>> -unsigned long tmp, tmp2;
>> +unsigned int tmp;
> 
> I reckon this should be int (the mask parameter is unsigned, but
> atomic_t.counter is signed).

For 'ldrex' and 'strex' (loading/storing instruction), it is really
better to match 'atomic_t.counter', but for 'bic' (operating
instruction), it is better to match 'mask'.

In my opinion, for signed/unsigned, 'operating' has higher priority than
'loading/storing' (especially for *mask functions, by default, suggest
using unsigned).

Commonly, for loading/storing (e.g. 'ldrex', 'strex'), must be sure of
bits wide (signed/unsigned will not cause real issues), but for
operating, signed/unsigned may cause real issues.


> 
>> +unsigned long tmp2;
>>  
>>  __asm__ __volatile__("@ atomic_clear_mask\n"
>>  "1: ldrex   %0, [%3]\n"
>> @@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
>> unsigned long *addr)
>>  "   strex   %1, %0, [%3]\n"
>>  "   teq %1, #0\n"
>>  "   bne 1b"
>> -: "=" (tmp), "=" (tmp2), "+Qo" (*addr)
>> -: "r" (addr), "Ir" (mask)
>> +: "=" (tmp), "=" (tmp2), "+Qo" (ptr->counter)
>> +: "r" (>counter), "Ir" (mask)
>>  : "cc");
>>  }
>>  
>> @@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
>> int new)
>>  return ret;
>>  }
>>  
>> -static inline void atomic_clear_mask(unsigned long mask, unsigned long 
>> *addr)
>> +static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
>>  {
>>  unsigned long flags;
>>  
>>  raw_local_irq_save(flags);
>> -*addr &= ~mask;
>> +v->counter &= ~mask;
>>  raw_local_irq_restore(flags);
>>  }
> 
> This is now identical to asm-generic/atomic.h. I wonder whether we could
> just #include that file for the ARMv6 case? You'd need to check the
> differences carefully.
> 

If most of functions for ARMv6 case can use "asm-generic/atomic.h", your
idea sounds good to me, although we don't need 'atomic_set_mask' (it is
inconsistent with 'atomic_clear_mask' in "asm-generic/atomic.h").

> Finally, I still question the need for the clear_mask function anyway. We
> don't implement set_mask, and these functions are only used by either other
> arch code or in drivers that don't work on ARM anyway.
> 

Hmm... can we remove atomic_*_mask() for both arm and arm64?

It seems before get a conclusion, it is necessary to let arm and arm64
pass 'allmodconfig' firstly (and then try to remove these functions to
see the compiling result).

I will/should try 'allmodconfig' for them, but excuse me, it needs
waiting (I am just trying 'arc' architecture with 'allmodconfig', and
already delayed, because I have no enough time resources on it :-( ).

> Will
> 
> 

Thanks.
-- 
Chen Gang
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Re: [PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-10 Thread Will Deacon 
On Thu, Oct 10, 2013 at 03:34:02AM +0100, Chen Gang wrote:
> In current kernel wide source, for arm, only s390 scsi drivers use
> atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
> 'atomic_t', so need match s390's atomic_clear_mask().
> 
> 
> Signed-off-by: Chen Gang 
> ---
>  arch/arm/include/asm/atomic.h |   13 +++--
>  1 files changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
> index da1c77d..0832a7f 100644
> --- a/arch/arm/include/asm/atomic.h
> +++ b/arch/arm/include/asm/atomic.h
> @@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, 
> int new)
>   return oldval;
>  }
>  
> -static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
> +static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
>  {
> - unsigned long tmp, tmp2;
> + unsigned int tmp;

I reckon this should be int (the mask parameter is unsigned, but
atomic_t.counter is signed).

> + unsigned long tmp2;
>  
>   __asm__ __volatile__("@ atomic_clear_mask\n"
>  "1:  ldrex   %0, [%3]\n"
> @@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
> unsigned long *addr)
>  "strex   %1, %0, [%3]\n"
>  "teq %1, #0\n"
>  "bne 1b"
> - : "=" (tmp), "=" (tmp2), "+Qo" (*addr)
> - : "r" (addr), "Ir" (mask)
> + : "=" (tmp), "=" (tmp2), "+Qo" (ptr->counter)
> + : "r" (>counter), "Ir" (mask)
>   : "cc");
>  }
>  
> @@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
> int new)
>   return ret;
>  }
>  
> -static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
> +static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
>  {
>   unsigned long flags;
>  
>   raw_local_irq_save(flags);
> - *addr &= ~mask;
> + v->counter &= ~mask;
>   raw_local_irq_restore(flags);
>  }

This is now identical to asm-generic/atomic.h. I wonder whether we could
just #include that file for the ARMv6 case? You'd need to check the
differences carefully.

Finally, I still question the need for the clear_mask function anyway. We
don't implement set_mask, and these functions are only used by either other
arch code or in drivers that don't work on ARM anyway.

Will
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Re: [PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-10 Thread Will Deacon 
On Thu, Oct 10, 2013 at 03:34:02AM +0100, Chen Gang wrote:
 In current kernel wide source, for arm, only s390 scsi drivers use
 atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
 'atomic_t', so need match s390's atomic_clear_mask().
 
 
 Signed-off-by: Chen Gang gang.c...@asianux.com
 ---
  arch/arm/include/asm/atomic.h |   13 +++--
  1 files changed, 7 insertions(+), 6 deletions(-)
 
 diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
 index da1c77d..0832a7f 100644
 --- a/arch/arm/include/asm/atomic.h
 +++ b/arch/arm/include/asm/atomic.h
 @@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, 
 int new)
   return oldval;
  }
  
 -static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
 +static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
  {
 - unsigned long tmp, tmp2;
 + unsigned int tmp;

I reckon this should be int (the mask parameter is unsigned, but
atomic_t.counter is signed).

 + unsigned long tmp2;
  
   __asm__ __volatile__(@ atomic_clear_mask\n
  1:  ldrex   %0, [%3]\n
 @@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
 unsigned long *addr)
  strex   %1, %0, [%3]\n
  teq %1, #0\n
  bne 1b
 - : =r (tmp), =r (tmp2), +Qo (*addr)
 - : r (addr), Ir (mask)
 + : =r (tmp), =r (tmp2), +Qo (ptr-counter)
 + : r (ptr-counter), Ir (mask)
   : cc);
  }
  
 @@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
 int new)
   return ret;
  }
  
 -static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
 +static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
  {
   unsigned long flags;
  
   raw_local_irq_save(flags);
 - *addr = ~mask;
 + v-counter = ~mask;
   raw_local_irq_restore(flags);
  }

This is now identical to asm-generic/atomic.h. I wonder whether we could
just #include that file for the ARMv6 case? You'd need to check the
differences carefully.

Finally, I still question the need for the clear_mask function anyway. We
don't implement set_mask, and these functions are only used by either other
arch code or in drivers that don't work on ARM anyway.

Will
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Re: [PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-10 Thread Chen Gang 
On 10/10/2013 05:58 PM, Will Deacon wrote:
 On Thu, Oct 10, 2013 at 03:34:02AM +0100, Chen Gang wrote:
 In current kernel wide source, for arm, only s390 scsi drivers use
 atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
 'atomic_t', so need match s390's atomic_clear_mask().


 Signed-off-by: Chen Gang gang.c...@asianux.com
 ---
  arch/arm/include/asm/atomic.h |   13 +++--
  1 files changed, 7 insertions(+), 6 deletions(-)

 diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
 index da1c77d..0832a7f 100644
 --- a/arch/arm/include/asm/atomic.h
 +++ b/arch/arm/include/asm/atomic.h
 @@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int 
 old, int new)
  return oldval;
  }
  
 -static inline void atomic_clear_mask(unsigned long mask, unsigned long 
 *addr)
 +static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
  {
 -unsigned long tmp, tmp2;
 +unsigned int tmp;
 
 I reckon this should be int (the mask parameter is unsigned, but
 atomic_t.counter is signed).

For 'ldrex' and 'strex' (loading/storing instruction), it is really
better to match 'atomic_t.counter', but for 'bic' (operating
instruction), it is better to match 'mask'.

In my opinion, for signed/unsigned, 'operating' has higher priority than
'loading/storing' (especially for *mask functions, by default, suggest
using unsigned).

Commonly, for loading/storing (e.g. 'ldrex', 'strex'), must be sure of
bits wide (signed/unsigned will not cause real issues), but for
operating, signed/unsigned may cause real issues.


 
 +unsigned long tmp2;
  
  __asm__ __volatile__(@ atomic_clear_mask\n
  1: ldrex   %0, [%3]\n
 @@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
 unsigned long *addr)
 strex   %1, %0, [%3]\n
 teq %1, #0\n
 bne 1b
 -: =r (tmp), =r (tmp2), +Qo (*addr)
 -: r (addr), Ir (mask)
 +: =r (tmp), =r (tmp2), +Qo (ptr-counter)
 +: r (ptr-counter), Ir (mask)
  : cc);
  }
  
 @@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
 int new)
  return ret;
  }
  
 -static inline void atomic_clear_mask(unsigned long mask, unsigned long 
 *addr)
 +static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
  {
  unsigned long flags;
  
  raw_local_irq_save(flags);
 -*addr = ~mask;
 +v-counter = ~mask;
  raw_local_irq_restore(flags);
  }
 
 This is now identical to asm-generic/atomic.h. I wonder whether we could
 just #include that file for the ARMv6 case? You'd need to check the
 differences carefully.
 

If most of functions for ARMv6 case can use asm-generic/atomic.h, your
idea sounds good to me, although we don't need 'atomic_set_mask' (it is
inconsistent with 'atomic_clear_mask' in asm-generic/atomic.h).

 Finally, I still question the need for the clear_mask function anyway. We
 don't implement set_mask, and these functions are only used by either other
 arch code or in drivers that don't work on ARM anyway.
 

Hmm... can we remove atomic_*_mask() for both arm and arm64?

It seems before get a conclusion, it is necessary to let arm and arm64
pass 'allmodconfig' firstly (and then try to remove these functions to
see the compiling result).

I will/should try 'allmodconfig' for them, but excuse me, it needs
waiting (I am just trying 'arc' architecture with 'allmodconfig', and
already delayed, because I have no enough time resources on it :-( ).

 Will
 
 

Thanks.
-- 
Chen Gang
--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-09 Thread Chen Gang 
In current kernel wide source, for arm, only s390 scsi drivers use
atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
'atomic_t', so need match s390's atomic_clear_mask().


Signed-off-by: Chen Gang 
---
 arch/arm/include/asm/atomic.h |   13 +++--
 1 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index da1c77d..0832a7f 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, 
int new)
return oldval;
 }
 
-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
 {
-   unsigned long tmp, tmp2;
+   unsigned int tmp;
+   unsigned long tmp2;
 
__asm__ __volatile__("@ atomic_clear_mask\n"
 "1:ldrex   %0, [%3]\n"
@@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
unsigned long *addr)
 "  strex   %1, %0, [%3]\n"
 "  teq %1, #0\n"
 "  bne 1b"
-   : "=" (tmp), "=" (tmp2), "+Qo" (*addr)
-   : "r" (addr), "Ir" (mask)
+   : "=" (tmp), "=" (tmp2), "+Qo" (ptr->counter)
+   : "r" (>counter), "Ir" (mask)
: "cc");
 }
 
@@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
int new)
return ret;
 }
 
-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
 {
unsigned long flags;
 
raw_local_irq_save(flags);
-   *addr &= ~mask;
+   v->counter &= ~mask;
raw_local_irq_restore(flags);
 }
 
-- 
1.7.7.6
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[PATCH 2/3] arm: include: asm: atomic.h: use 'unsigned int' and 'atomic' instead of 'unsigned long' for atomic_clear_mask()

2013-10-09 Thread Chen Gang 
In current kernel wide source, for arm, only s390 scsi drivers use
atomic_clear_mask(), now, s390 itself need use 'unsigned int' and
'atomic_t', so need match s390's atomic_clear_mask().


Signed-off-by: Chen Gang gang.c...@asianux.com
---
 arch/arm/include/asm/atomic.h |   13 +++--
 1 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index da1c77d..0832a7f 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -134,9 +134,10 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, 
int new)
return oldval;
 }
 
-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *ptr)
 {
-   unsigned long tmp, tmp2;
+   unsigned int tmp;
+   unsigned long tmp2;
 
__asm__ __volatile__(@ atomic_clear_mask\n
 1:ldrex   %0, [%3]\n
@@ -144,8 +145,8 @@ static inline void atomic_clear_mask(unsigned long mask, 
unsigned long *addr)
   strex   %1, %0, [%3]\n
   teq %1, #0\n
   bne 1b
-   : =r (tmp), =r (tmp2), +Qo (*addr)
-   : r (addr), Ir (mask)
+   : =r (tmp), =r (tmp2), +Qo (ptr-counter)
+   : r (ptr-counter), Ir (mask)
: cc);
 }
 
@@ -197,12 +198,12 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, 
int new)
return ret;
 }
 
-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
 {
unsigned long flags;
 
raw_local_irq_save(flags);
-   *addr = ~mask;
+   v-counter = ~mask;
raw_local_irq_restore(flags);
 }
 
-- 
1.7.7.6
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