perf env: Also consider env->arch == NULL as local operation

We'll set a new machine field based on env->arch, which for live mode,
like with 'perf top' means we need to use uname() to figure the name of
the arch, fix perf_env__arch() to consider both (env == NULL) and
(env->arch == NULL) as local operation.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: stable@vger.kernel.org # 4.19
Link: https://lkml.kernel.org/n/tip-vcz4ufzdon7cwy8dm2ua53xk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 59f38c7693f8648b7ce494edc864f09a0f6b09d5..4c23779e271a31ce66d0deeb527a658e0ae90ae7 100644 (file)
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -166,7 +166,7 @@ const char *perf_env__arch(struct perf_env *env)
        struct utsname uts;
        char *arch_name;
 
-       if (!env) { /* Assume local operation */
+       if (!env || !env->arch) { /* Assume local operation */
                if (uname(&uts) < 0)
                        return NULL;
                arch_name = uts.machine;