question: attribute 'require_context'

question: attribute 'require_context'

[H Hartley Sweeten]

Hello all,

I'm trying to do an allyesconfig build of the kernel on an old debian box
with gcc version, gcc (Debian 4.3.2-1.1) 4.3.2. Everything goes fine until
the DRBD device driver gets compiled. At that point I get a bunch of
error messages like this:

drivers/block/drbd/drbd_int.h:974:39 error: attribute 'require_context': unknown attribute

It looks like this is due to the following:

#ifdef __CHECKER__
# define __protected_by(x)       __attribute__((require_context(x,1,999,"rdwr")))
# define __protected_read_by(x)  __attribute__((require_context(x,1,999,"read")))
# define __protected_write_by(x) __attribute__((require_context(x,1,999,"write")))
# define __must_hold(x)       __attribute__((context(x,1,1), require_context(x,1,999,"call")))
#else
# define __protected_by(x)
# define __protected_read_by(x)
# define __protected_write_by(x)
# define __must_hold(x)
#endif

Is the require_context attribute something found in a later version of gcc?

Thanks,
Hartley

Re: question: attribute 'require_context'

[Randy Dunlap]

On 09/09/11 17:47, H Hartley Sweeten wrote:
> Hello all,
> 
> I'm trying to do an allyesconfig build of the kernel on an old debian box
> with gcc version, gcc (Debian 4.3.2-1.1) 4.3.2. Everything goes fine until
> the DRBD device driver gets compiled. At that point I get a bunch of
> error messages like this:
> 
> drivers/block/drbd/drbd_int.h:974:39 error: attribute 'require_context': unknown attribute
> 
> It looks like this is due to the following:
> 
> #ifdef __CHECKER__
> # define __protected_by(x)       __attribute__((require_context(x,1,999,"rdwr")))
> # define __protected_read_by(x)  __attribute__((require_context(x,1,999,"read")))
> # define __protected_write_by(x) __attribute__((require_context(x,1,999,"write")))
> # define __must_hold(x)       __attribute__((context(x,1,1), require_context(x,1,999,"call")))
> #else
> # define __protected_by(x)
> # define __protected_read_by(x)
> # define __protected_write_by(x)
> # define __must_hold(x)
> #endif
> 
> Is the require_context attribute something found in a later version of gcc?

No, it's a proposed change (patch) to sparse.

You can see all sparse mailing list messages about that patch and other
questions about it by searching the linux-sparse archives at marc.info:
  http://marc.info/?l=linux-sparse&w=2&r=1&s=require_context&q=b


-- 
~Randy
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