perf vendor events: Drop incomplete multiple mapfile support

Currently jevents supports multiple mapfiles, but this is only in the
form where mapfile basename starts with 'mapfile.csv'

At the moment, no architectures actually use multiple mapfiles, so drop
the support for now.

This patch also solves a nuisance where, when the mapfile is edited and
the text editor may create a backup, jevents may use the backup, as
shown:

  jevents: Many mapfiles? Using pmu-events/arch/arm64/mapfile.csv~, ignoring pmu-events/arch/arm64/mapfile.csv

Signed-off-by: John Garry <john.garry@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxarm@huawei.com
Link: http://lkml.kernel.org/r/1520506716-197429-2-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/README

@@ -11,9 +11,8 @@ tree tools/perf/pmu-events/arch/foo.
 	- Regular files with '.json' extension in the name are assumed to be
 	  JSON files, each of which describes a set of PMU events.
 
-	- Regular files with basename starting with 'mapfile.csv' are assumed
-	  to be a CSV file that maps a specific CPU to its set of PMU events.
-	  (see below for mapfile format)
+	- The CSV file that maps a specific CPU to its set of PMU events is to
+	  be named 'mapfile.csv' (see below for mapfile format).
 
 	- Directories are traversed, but all other files are ignored.
 

tools/perf/pmu-events/jevents.c

@@ -798,16 +798,10 @@ static int process_one_file(const char *fpath, const struct stat *sb,
 	 * after processing all JSON files (so we can write out the
 	 * mapping table after all PMU events tables).
 	 *
-	 * TODO: Allow for multiple mapfiles? Punt for now.
 	 */
 	if (level == 1 && is_file) {
-		if (!strncmp(bname, "mapfile.csv", 11)) {
-			if (mapfile) {
-				pr_info("%s: Many mapfiles? Using %s, ignoring %s\n",
-						prog, mapfile, fpath);
-			} else {
-				mapfile = strdup(fpath);
-			}
+		if (!strcmp(bname, "mapfile.csv")) {
+			mapfile = strdup(fpath);
 			return 0;
 		}