proc: move /proc/diskstats boilerplate to block/genhd.c

[safe/jmp/linux-2.6] / include / linux / cpumask.h

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 1b5c98e..d3219d7 100644 (file)
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -62,15 +62,7 @@
  * int next_cpu_nr(cpu, mask)          Next cpu past 'cpu', or nr_cpu_ids
  *
  * cpumask_t cpumask_of_cpu(cpu)       Return cpumask with bit 'cpu' set
- *ifdef CONFIG_HAS_CPUMASK_OF_CPU
- * cpumask_of_cpu_ptr_declare(v)       Declares cpumask_t *v
- * cpumask_of_cpu_ptr_next(v, cpu)     Sets v = &cpumask_of_cpu_map[cpu]
- * cpumask_of_cpu_ptr(v, cpu)          Combines above two operations
- *else
- * cpumask_of_cpu_ptr_declare(v)       Declares cpumask_t _v and *v = &_v
- * cpumask_of_cpu_ptr_next(v, cpu)     Sets _v = cpumask_of_cpu(cpu)
- * cpumask_of_cpu_ptr(v, cpu)          Combines above two operations
- *endif
+ *                                     (can be used as an lvalue)
  * CPU_MASK_ALL                                Initializer - all bits set
  * CPU_MASK_NONE                       Initializer - no bits set
  * unsigned long *cpus_addr(mask)      Array of unsigned long's in mask
@@ -273,37 +265,30 @@ static inline void __cpus_shift_left(cpumask_t *dstp,
        bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
 }
 
+/*
+ * Special-case data structure for "single bit set only" constant CPU masks.
+ *
+ * We pre-generate all the 64 (or 32) possible bit positions, with enough
+ * padding to the left and the right, and return the constant pointer
+ * appropriately offset.
+ */
+extern const unsigned long
+       cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)];
+
+static inline const cpumask_t *get_cpu_mask(unsigned int cpu)
+{
+       const unsigned long *p = cpu_bit_bitmap[1 + cpu % BITS_PER_LONG];
+       p -= cpu / BITS_PER_LONG;
+       return (const cpumask_t *)p;
+}
+
+/*
+ * In cases where we take the address of the cpumask immediately,
+ * gcc optimizes it out (it's a constant) and there's no huge stack
+ * variable created:
+ */
+#define cpumask_of_cpu(cpu) (*get_cpu_mask(cpu))
 
-#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP
-extern cpumask_t *cpumask_of_cpu_map;
-#define cpumask_of_cpu(cpu)    (cpumask_of_cpu_map[cpu])
-#define        cpumask_of_cpu_ptr(v, cpu)                                      \
-               const cpumask_t *v = &cpumask_of_cpu(cpu)
-#define        cpumask_of_cpu_ptr_declare(v)                                   \
-               const cpumask_t *v
-#define cpumask_of_cpu_ptr_next(v, cpu)                                        \
-                                       v = &cpumask_of_cpu(cpu)
-#else
-#define cpumask_of_cpu(cpu)                                            \
-({                                                                     \
-       typeof(_unused_cpumask_arg_) m;                                 \
-       if (sizeof(m) == sizeof(unsigned long)) {                       \
-               m.bits[0] = 1UL<<(cpu);                                 \
-       } else {                                                        \
-               cpus_clear(m);                                          \
-               cpu_set((cpu), m);                                      \
-       }                                                               \
-       m;                                                              \
-})
-#define        cpumask_of_cpu_ptr(v, cpu)                                      \
-               cpumask_t _##v = cpumask_of_cpu(cpu);                   \
-               const cpumask_t *v = &_##v
-#define        cpumask_of_cpu_ptr_declare(v)                                   \
-               cpumask_t _##v;                                         \
-               const cpumask_t *v = &_##v
-#define cpumask_of_cpu_ptr_next(v, cpu)                                        \
-                                       _##v = cpumask_of_cpu(cpu)
-#endif
 
 #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)