[tip:perf/core] perf trace: Fix exclusion of not available syscall names from selector list

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  a4066d64d9391a734ee0e49c8d2757f5685013b4
Gitweb:     https://git.kernel.org/tip/a4066d64d9391a734ee0e49c8d2757f5685013b4
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Thu, 13 Jun 2019 17:35:09 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 17 Jun 2019 15:57:19 -0300

perf trace: Fix exclusion of not available syscall names from selector list

We were just skipping the syscalls not available in a particular
architecture without reflecting this in the number of entries in the
ev_qualifier_ids.nr variable, fix it.

This was done with the most minimalistic way, reusing the index variable
'i', a followup patch will further clean this by making 'i' renamed to
'nr_used' and using 'nr_allocated' in a few more places.

Reported-by: Leo Yan <leo.yan@xxxxxxxxxx>
Tested-by: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Fixes: 04c41bcb862b ("perf trace: Skip unknown syscalls when expanding strace like syscall groups")
Link: https://lkml.kernel.org/r/20190613181514.GC1402@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 12f5ad98f8c1..fa9eb467eb4c 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1527,9 +1527,9 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 
 static int trace__validate_ev_qualifier(struct trace *trace)
 {
-	int err = 0, i;
+	int err = 0;
 	bool printed_invalid_prefix = false;
-	size_t nr_allocated;
+	size_t nr_allocated, i;
 	struct str_node *pos;
 
 	trace->ev_qualifier_ids.nr = strlist__nr_entries(trace->ev_qualifier);
@@ -1574,7 +1574,7 @@ matches:
 			id = syscalltbl__strglobmatch_next(trace->sctbl, sc, &match_next);
 			if (id < 0)
 				break;
-			if (nr_allocated == trace->ev_qualifier_ids.nr) {
+			if (nr_allocated == i) {
 				void *entries;
 
 				nr_allocated += 8;
@@ -1587,11 +1587,11 @@ matches:
 				}
 				trace->ev_qualifier_ids.entries = entries;
 			}
-			trace->ev_qualifier_ids.nr++;
 			trace->ev_qualifier_ids.entries[i++] = id;
 		}
 	}
 
+	trace->ev_qualifier_ids.nr = i;
 out:
 	if (printed_invalid_prefix)
 		pr_debug("\n");