Re: [PATCH 7/8] cpumask: Provide a generic set of CPUMASK_ALLOC macros

["Bert Wesarg" <bert.wesarg@googlemail.com>]

On Tue, Jul 15, 2008 at 23:14, Mike Travis <travis@sgi.com> wrote:
>  * Provide a generic set of CPUMASK_ALLOC macros patterned after the
>    SCHED_CPUMASK_ALLOC macros.  This is used where multiple cpumask_t
>    variables are declared on the stack to reduce the amount of stack
>    space required.
>
> Based on linux-2.6.tip/master at the following commit:
>
>    commit 0a91813e16ebd5c2d9b5c2acd5b7c91742112c4f
>    Merge: 9a635fa... 724dce0...
>    Author: Ingo Molnar <mingo@elte.hu>
>    Date:   Tue Jul 15 14:55:17 2008 +0200
>
> Signed-off-by: Mike Travis <travis@sgi.com>
> Cc: Paul Jackson <pj@sgi.com>
> ---
>  include/linux/cpumask.h |   21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> --- linux-2.6.tip.orig/include/linux/cpumask.h
> +++ linux-2.6.tip/include/linux/cpumask.h
> @@ -75,6 +75,17 @@
>  * CPU_MASK_NONE                       Initializer - no bits set
>  * unsigned long *cpus_addr(mask)      Array of unsigned long's in mask
>  *
> + *if NR_CPUS > BITS_PER_LONG
> + *   CPUMASK_ALLOC(m)                  Declares and allocates struct m *m =
> + *                                        (struct m *)kmalloc(sizeof(*m), ...)
Shouldn't you mention the GFP_KERNEL flag? And the cast should not
necessarily be mentioned in a comment.

> + *   CPUMASK_FREE(m)                   Macro for kfree(v)
                                                    kfree(m)

> + *else
> + *   CPUMASK_ALLOC(m)                  Declares struct m _m, *m = &_m
> + *   CPUMASK_FREE(m)                   Nop
> + *endif
> + *   CPUMASK_VAR(v, m)                 Declares cpumask_t *v =
> + *                                             m + offset(struct m, v)
                                                      offsetof
and why can't you use a &(m->v)?

Regards
Bert