Re: [patch 1/2] spinlocks: check spinlock_t/rwlock_t argument type on non-SMP builds

Re: [patch 1/2] spinlocks: check spinlock_t/rwlock_t argument type on non-SMP builds

[Ingo Molnar]

* akpm@linux-foundation.org <akpm@linux-foundation.org> wrote:

> From: David Kilroy <kilroyd@googlemail.com>
> 
> When writing code for UP without CONFIG_DEBUG_SPINLOCK it's easy to get
> the first argument to the spinlock/rwlock functions wrong.  This is
> because the parameter is not actually used in this configuration.
> 
> Typically you will only find out it's wrong
>  * by rebuilding with CONFIG_SMP or CONFIG_DEBUG_SPINLOCK
>  * after you've submitted your beautiful patch series.
> 
> The first means a long wait, and the latter is a bit late.
> 
> Change the intermediate macros into inline functions.
> 
> Signed-off-by: David Kilroy <kilroyd@googlemail.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  include/linux/spinlock.h        |    6 -
>  include/linux/spinlock_api_up.h |  118 ++++++++++++++++++++++--------
>  2 files changed, 92 insertions(+), 32 deletions(-)
> 
> diff -puN include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds include/linux/spinlock.h
> --- a/include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds
> +++ a/include/linux/spinlock.h
> @@ -240,17 +240,17 @@ static inline void smp_mb__after_lock(vo
>  #define spin_lock_irqsave(lock, flags)			\
>  	do {						\
>  		typecheck(unsigned long, flags);	\
> -		_spin_lock_irqsave(lock, flags);	\
> +		_spin_lock_irqsave(lock, &flags);	\
>  	} while (0)
>  #define read_lock_irqsave(lock, flags)			\
>  	do {						\
>  		typecheck(unsigned long, flags);	\
> -		_read_lock_irqsave(lock, flags);	\
> +		_read_lock_irqsave(lock, &flags);	\
>  	} while (0)

these bits broke the Alpha build:

/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readb':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:451: error: '_spin_lock_irqsave' is static but used in inline function 't2_readb' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:456: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_readb' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readw':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:465: error: '_spin_lock_irqsave' is static but used in inline function 't2_readw' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:470: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_readw' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readl':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:483: error: '_spin_lock_irqsave' is static but used in inline function 't2_readl' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:488: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_readl' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readq':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:497: error: '_spin_lock_irqsave' is static but used in inline function 't2_readq' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:504: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_readq' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_writeb':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:513: error: '_spin_lock_irqsave' is static but used in inline function 't2_writeb' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:519: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_writeb' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_writew':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:527: error: '_spin_lock_irqsave' is static but used in inline function 't2_writew' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:533: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_writew' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_writel':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:545: error: '_spin_lock_irqsave' is static but used in inline function 't2_writel' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:550: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_writel' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_writeq':
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:558: error: '_spin_lock_irqsave' is static but used in inline function 't2_writeq' which is not static
/home/mingo/tip/arch/alpha/include/asm/core_t2.h:565: error: '_spin_unlock_irqrestore' is static but used in inline function 't2_writeq' which is not static
make[2]: *** [arch/alpha/kernel/sys_sable.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [arch/alpha/kernel] Error 2
make[1]: *** Waiting for unfinished jobs....

so i've dropped them for now.

	Ingo

Re: [patch 1/2] spinlocks: check spinlock_t/rwlock_t argument type on non-SMP builds

[Andrew Morton]

On Mon, 21 Sep 2009 09:43:52 +0200
Ingo Molnar <mingo@elte.hu> wrote:

> 
> * akpm@linux-foundation.org <akpm@linux-foundation.org> wrote:
> 
> > From: David Kilroy <kilroyd@googlemail.com>
> > 
> > When writing code for UP without CONFIG_DEBUG_SPINLOCK it's easy to get
> > the first argument to the spinlock/rwlock functions wrong.  This is
> > because the parameter is not actually used in this configuration.
> > 
> > Typically you will only find out it's wrong
> >  * by rebuilding with CONFIG_SMP or CONFIG_DEBUG_SPINLOCK
> >  * after you've submitted your beautiful patch series.
> > 
> > The first means a long wait, and the latter is a bit late.
> > 
> > Change the intermediate macros into inline functions.
> > 
> > Signed-off-by: David Kilroy <kilroyd@googlemail.com>
> > Cc: Ingo Molnar <mingo@elte.hu>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  include/linux/spinlock.h        |    6 -
> >  include/linux/spinlock_api_up.h |  118 ++++++++++++++++++++++--------
> >  2 files changed, 92 insertions(+), 32 deletions(-)
> > 
> > diff -puN include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds include/linux/spinlock.h
> > --- a/include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds
> > +++ a/include/linux/spinlock.h
> > @@ -240,17 +240,17 @@ static inline void smp_mb__after_lock(vo
> >  #define spin_lock_irqsave(lock, flags)			\
> >  	do {						\
> >  		typecheck(unsigned long, flags);	\
> > -		_spin_lock_irqsave(lock, flags);	\
> > +		_spin_lock_irqsave(lock, &flags);	\
> >  	} while (0)
> >  #define read_lock_irqsave(lock, flags)			\
> >  	do {						\
> >  		typecheck(unsigned long, flags);	\
> > -		_read_lock_irqsave(lock, flags);	\
> > +		_read_lock_irqsave(lock, &flags);	\
> >  	} while (0)
> 
> these bits broke the Alpha build:
> 
> /home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readb':
> /home/mingo/tip/arch/alpha/include/asm/core_t2.h:451: error: '_spin_lock_irqsave' is static but used in inline function 't2_readb' which is not static

hm.  What the heck does that mean?

__EXTERN_INLINE u8 t2_readb(const volatile void __iomem *xaddr)

Something to do with the extern-inline?


Do you have the .config?  My alpha builds went OK.

Re: [patch 1/2] spinlocks: check spinlock_t/rwlock_t argument type on non-SMP builds

[Dave]

Andrew Morton wrote:
> On Mon, 21 Sep 2009 09:43:52 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
> 
>> * akpm@linux-foundation.org <akpm@linux-foundation.org> wrote:
>>
>>> From: David Kilroy <kilroyd@googlemail.com>
>>>
>>> When writing code for UP without CONFIG_DEBUG_SPINLOCK it's easy to get
>>> the first argument to the spinlock/rwlock functions wrong.  This is
>>> because the parameter is not actually used in this configuration.
>>>
>>> Typically you will only find out it's wrong
>>>  * by rebuilding with CONFIG_SMP or CONFIG_DEBUG_SPINLOCK
>>>  * after you've submitted your beautiful patch series.
>>>
>>> The first means a long wait, and the latter is a bit late.
>>>
>>> Change the intermediate macros into inline functions.
>>>
>>> Signed-off-by: David Kilroy <kilroyd@googlemail.com>
>>> Cc: Ingo Molnar <mingo@elte.hu>
>>> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
>>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>>> ---
>>>
>>>  include/linux/spinlock.h        |    6 -
>>>  include/linux/spinlock_api_up.h |  118 ++++++++++++++++++++++--------
>>>  2 files changed, 92 insertions(+), 32 deletions(-)
>>>
>>> diff -puN include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds include/linux/spinlock.h
>>> --- a/include/linux/spinlock.h~spinlocks-check-spinlock_t-rwlock_t-argument-type-on-non-smp-builds
>>> +++ a/include/linux/spinlock.h
>>> @@ -240,17 +240,17 @@ static inline void smp_mb__after_lock(vo
>>>  #define spin_lock_irqsave(lock, flags)			\
>>>  	do {						\
>>>  		typecheck(unsigned long, flags);	\
>>> -		_spin_lock_irqsave(lock, flags);	\
>>> +		_spin_lock_irqsave(lock, &flags);	\
>>>  	} while (0)
>>>  #define read_lock_irqsave(lock, flags)			\
>>>  	do {						\
>>>  		typecheck(unsigned long, flags);	\
>>> -		_read_lock_irqsave(lock, flags);	\
>>> +		_read_lock_irqsave(lock, &flags);	\
>>>  	} while (0)
>> these bits broke the Alpha build:
>>
>> /home/mingo/tip/arch/alpha/include/asm/core_t2.h: In function 't2_readb':
>> /home/mingo/tip/arch/alpha/include/asm/core_t2.h:451: error: '_spin_lock_irqsave' is static but used in inline function 't2_readb' which is not static
> 
> hm.  What the heck does that mean?
> 
> __EXTERN_INLINE u8 t2_readb(const volatile void __iomem *xaddr)
> 
> Something to do with the extern-inline?

This came up the last time this went into Ingos tree. And yes, it's the
extern inlines using the spinlock functions that causes the error.

> Do you have the .config?  My alpha builds went OK.

Last I checked, you need to have:
CONFIG_SMP=N
CONFIG_DEBUG_SPINLOCK=N

The latter gets auto-selected, so I set:
CONFIG_DEBUG_LOCK_ALLOC=N
CONFIG_LOCK_STAT=N
CONFIG_PROVE_LOCKING=N
CONFIG_LOCK_STAT=N


Regards,

Dave.