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Diffstat (limited to 'include/linux/cpumask.h')
-rw-r--r--include/linux/cpumask.h63
1 files changed, 24 insertions, 39 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 1b5c98e7fef..96d0509fb8d 100644
--- 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)