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>
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 72f9c32..30d59d1 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -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 @@
#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)