Re: warnings in git-wireless

Re: warnings in git-wireless

[Andrew Morton]

On Wed, 06 Jun 2007 15:33:46 -0700 James Ketrenos <jketreno@linux.intel.com> wrote:

> Andrew Morton wrote:
> > On Wed, 06 Jun 2007 13:51:41 -0700 James Ketrenos <jketreno@linux.intel.com> wrote:
> > 
> >>>>  * make C=2 CF=-Wall will complain if you use ARRAY_SIZE on global data
> >>>>  */
> >>>> #define GLOBAL_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> >>> This is identical to ARRAY_SIZE.
> >>>
> >>> And if there's some problem with ARRAY_SIZE then fix ARRAY_SIZE!  Don't go 
> >>> off and create some private thing and leave everyone else twisting in the
> >>> wind.
> >> The code was resolving the sparse warnings.  
> > 
> ...
> > Your GLOBAL_ARRAY_SIZE() is, afaict, identical to ARRAY_SIZE().
> 
> >From include/linux/kernel.h
> 
> #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))

o crap, sorry, I was looking at one of the other definitions of ARRAY_SIZE :(


> >From drivers/net/wireless/mac80211/iwlwifi/iwl-helpers.h
> 
> #define GLOBAL_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> 
> The '+ __must_be_array(arr)' part of ARRAY_SIZE was causing sparse to complain 
> with:
> 
> drivers/net/wireless/mac80211/iwlwifi/base.c:4646:22: error: cannot size expression
> ...

OK, that's a problem in sparse, I guess.

There _should_ be some #ifdeffable thing which is being passed to cpp when
we run sparse (but I'm not sure what it is).  If there is such a thing then
we could disable the __must_be_array() thing during sparse runs.

But longer-term, sparse should be taught about __must_be_array().

> When I had run my builds, I had restricted the sparse checks to just iwlwifi 
> (vs. checking the rest of the kernel).
> 
> I just ran it C=2 CF=-Wall against the rest of the kernel and do see other code 
> with the same problem, eg:
> 
> sound/core/memalloc.c:521:14: error: cannot size expression
> ...
> 
> I had erroneously thought it was just a problem with iwlwifi...
> 

Re: warnings in git-wireless

[Dave Jones]

On Wed, Jun 06, 2007 at 06:04:21PM -0700, Andrew Morton wrote:

 > There _should_ be some #ifdeffable thing which is being passed to cpp when
 > we run sparse (but I'm not sure what it is).

#ifdef __CHECKER__

(See include/linux/compiler.h, this is how we implement __user & friends)

	Dave

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