cpumask: Provide a generic set of CPUMASK_ALLOC macros, FIXUP

* Rename CPUMASK_VAR --> CPUMASK_PTR (and simplify)

  * Fix a semantic error in CPUMASK_ALLOC

  * Add a bit of commentry to cpumask.h

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Mike Travis 2008-07-18 18:11:33 -07:00 committed by Ingo Molnar
parent b38868aabe
commit 80422d3431

View file

@ -75,16 +75,36 @@
* CPU_MASK_NONE Initializer - no bits set
* unsigned long *cpus_addr(mask) Array of unsigned long's in mask
*
* CPUMASK_ALLOC kmalloc's a structure that is a composite of many cpumask_t
* variables, and CPUMASK_PTR provides pointers to each field.
*
* The structure should be defined something like this:
* struct my_cpumasks {
* cpumask_t mask1;
* cpumask_t mask2;
* };
*
* Usage is then:
* CPUMASK_ALLOC(my_cpumasks);
* CPUMASK_PTR(mask1, my_cpumasks);
* CPUMASK_PTR(mask2, my_cpumasks);
*
* --- DO NOT reference cpumask_t pointers until this check ---
* if (my_cpumasks == NULL)
* "kmalloc failed"...
*
* References are now pointers to the cpumask_t variables (*mask1, ...)
*
*if NR_CPUS > BITS_PER_LONG
* CPUMASK_ALLOC(m) Declares and allocates struct m *m =
* (struct m *)kmalloc(sizeof(*m), ...)
* CPUMASK_FREE(m) Macro for kfree(v)
* kmalloc(sizeof(*m), GFP_KERNEL)
* CPUMASK_FREE(m) Macro for 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)
* CPUMASK_PTR(v, m) Declares cpumask_t *v = &(m->v)
* ------------------------------------------------------------------------
*
* int cpumask_scnprintf(buf, len, mask) Format cpumask for printing
* int cpumask_parse_user(ubuf, ulen, mask) Parse ascii string as cpumask
@ -326,11 +346,10 @@ extern cpumask_t cpu_mask_all;
#define CPUMASK_ALLOC(m) struct m *m = kmalloc(sizeof(*m), GFP_KERNEL)
#define CPUMASK_FREE(m) kfree(m)
#else
#define CPUMASK_ALLOC(m) struct allmasks _m, *m = &_m
#define CPUMASK_ALLOC(m) struct m _m, *m = &_m
#define CPUMASK_FREE(m)
#endif
#define CPUMASK_VAR(v, m) cpumask_t *v = (cpumask_t *) \
((unsigned long)(m) + offsetof(struct m, v))
#define CPUMASK_PTR(v, m) cpumask_t *v = &(m->v)
#define cpumask_scnprintf(buf, len, src) \
__cpumask_scnprintf((buf), (len), &(src), NR_CPUS)