* Re: warnings in git-wireless
[not found] ` <4667364A.4040803@linux.intel.com>
@ 2007-06-07 1:04 ` Andrew Morton
2007-06-07 1:13 ` Dave Jones
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Morton @ 2007-06-07 1:04 UTC (permalink / raw)
To: James Ketrenos; +Cc: NetDev, linux-wireless, linux-sparse
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...
>
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