[PATCH v2 2/3] perf mmap: declare type for cpu mask of arbitrary length

[Alexey Budankov]

Declare a dedicated struct map_cpu_mask type for cpu masks of
arbitrary length. Mask is available thru bits pointer and the
mask length is kept in nbits field. MMAP_CPU_MASK_BYTES() macro
returns mask storage size in bytes.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
Changes in v2:
- capitalized MMAP_CPU_MASK_BYTES() macro

---
 tools/perf/util/mmap.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index bee4e83f7109..786c235d6062 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -15,6 +15,15 @@
 #include "event.h"
 
 struct aiocb;
+
+struct mmap_cpu_mask {
+	unsigned long *bits;
+	size_t nbits;
+};
+
+#define MMAP_CPU_MASK_BYTES(m) \
+	(BITS_TO_LONGS(((struct mmap_cpu_mask *)m)->nbits) * sizeof(unsigned long))
+
 /**
  * struct mmap - perf's ring buffer mmap details
  *
-- 
2.20.1