[PATCH 4.2 114/120] dm stats: report precise_timestamps and histogram in @stats_list output

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

commit bd49784fd1e8f42c7600fbfa206361324857f373 upstream.

If the user selected the precise_timestamps or histogram options, report
it in the @stats_list message output.

If the user didn't select these options, no extra tokens are reported,
thus it is backward compatible with old software that doesn't know about
precise timestamps and histogram.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.2
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 Documentation/device-mapper/statistics.txt |    4 ++++
 drivers/md/dm-stats.c                      |   14 +++++++++++++-
 include/uapi/linux/dm-ioctl.h              |    4 ++--
 3 files changed, 19 insertions(+), 3 deletions(-)

--- a/Documentation/device-mapper/statistics.txt
+++ b/Documentation/device-mapper/statistics.txt
@@ -121,6 +121,10 @@ Messages
 
 	Output format:
 	  <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
+	        precise_timestamps histogram:n1,n2,n3,...
+
+	The strings "precise_timestamps" and "histogram" are printed only
+	if they were specified when creating the region.
 
     @stats_print <region_id> [<starting_line> <number_of_lines>]
 
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -457,12 +457,24 @@ static int dm_stats_list(struct dm_stats
 	list_for_each_entry(s, &stats->list, list_entry) {
 		if (!program || !strcmp(program, s->program_id)) {
 			len = s->end - s->start;
-			DMEMIT("%d: %llu+%llu %llu %s %s\n", s->id,
+			DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
 				(unsigned long long)s->start,
 				(unsigned long long)len,
 				(unsigned long long)s->step,
 				s->program_id,
 				s->aux_data);
+			if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
+				DMEMIT(" precise_timestamps");
+			if (s->n_histogram_entries) {
+				unsigned i;
+				DMEMIT(" histogram:");
+				for (i = 0; i < s->n_histogram_entries; i++) {
+					if (i)
+						DMEMIT(",");
+					DMEMIT("%llu", s->histogram_boundaries[i]);
+				}
+			}
+			DMEMIT("\n");
 		}
 	}
 	mutex_unlock(&stats->mutex);
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -267,9 +267,9 @@ enum {
 #define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 
 #define DM_VERSION_MAJOR	4
-#define DM_VERSION_MINOR	32
+#define DM_VERSION_MINOR	33
 #define DM_VERSION_PATCHLEVEL	0
-#define DM_VERSION_EXTRA	"-ioctl (2015-6-26)"
+#define DM_VERSION_EXTRA	"-ioctl (2015-8-18)"
 
 /* Status bits */
 #define DM_READONLY_FLAG	(1 << 0) /* In/Out */


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