perf pmu: Remove logic for PMU name being NULL

The PMU name could be NULL in the case of the fake_pmu. Initialize the
name for the fake_pmu to "fake" so that all other logic can assume it
is initialized. Add a const to the type of name so that a literal can
be used to avoid additional initialization code. Propagate the cost
through related routines and remove now unnecessary "(char *)"
casts. Doing this located a bug in builtin-list for the pmu_glob that
was missing a strdup.

Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20230825024002.801955-3-irogers@google.com
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Wei Li <liwei391@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ming Wang <wangming01@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
index c07fe3a90722..39ffe8ceb380 100644
--- a/tools/perf/util/mem-events.c
+++ b/tools/perf/util/mem-events.c
@@ -37,7 +37,7 @@ struct perf_mem_event * __weak perf_mem_events__ptr(int i)
 	return &perf_mem_events[i];
 }
 
-char * __weak perf_mem_events__name(int i, char *pmu_name  __maybe_unused)
+const char * __weak perf_mem_events__name(int i, const char *pmu_name  __maybe_unused)
 {
 	struct perf_mem_event *e = perf_mem_events__ptr(i);
 
@@ -53,7 +53,7 @@ char * __weak perf_mem_events__name(int i, char *pmu_name  __maybe_unused)
 		return mem_loads_name;
 	}
 
-	return (char *)e->name;
+	return e->name;
 }
 
 __weak bool is_mem_loads_aux_event(struct evsel *leader __maybe_unused)
@@ -186,7 +186,6 @@ int perf_mem_events__record_args(const char **rec_argv, int *argv_nr,
 	int i = *argv_nr, k = 0;
 	struct perf_mem_event *e;
 	struct perf_pmu *pmu;
-	char *s;
 
 	for (int j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
 		e = perf_mem_events__ptr(j);
@@ -209,15 +208,16 @@ int perf_mem_events__record_args(const char **rec_argv, int *argv_nr,
 			}
 
 			while ((pmu = perf_pmus__scan(pmu)) != NULL) {
+				const char *s = perf_mem_events__name(j, pmu->name);
+
 				rec_argv[i++] = "-e";
-				s = perf_mem_events__name(j, pmu->name);
 				if (s) {
-					s = strdup(s);
-					if (!s)
+					char *copy = strdup(s);
+					if (!copy)
 						return -1;
 
-					rec_argv[i++] = s;
-					rec_tmp[k++] = s;
+					rec_argv[i++] = copy;
+					rec_tmp[k++] = copy;
 				}
 			}
 		}