perf data: Add global path holder

Add a 'path' member to 'struct perf_data'. It will keep the configured
path for the data (const char *). The path in struct perf_data_file is
now dynamically allocated (duped) from it.

This scheme is useful/used in following patches where struct
perf_data::path holds the 'configure' directory path and struct
perf_data_file::path holds the allocated path for specific files.

Also it actually makes the code little simpler.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20190221094145.9151-3-jolsa@kernel.org
[ Fixup data-convert-bt.c missing conversion ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index b80ec08..fa520f4 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -1949,7 +1949,7 @@ int cmd_kmem(int argc, const char **argv)
 		return __cmd_record(argc, argv);
 	}
 
-	data.file.path = input_name;
+	data.path = input_name;
 
 	kmem_session = session = perf_session__new(&data, false, &perf_kmem);
 	if (session == NULL)