perf buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid

Use path/to/bin/buildid/elf instead of path/to/bin/buildid
to store corresponding elf binary.
This also stores vdso in buildid/vdso, kallsyms in buildid/kallsyms.

Note that the existing caches are not updated until user adds
or updates the cache. Anyway, if there is the old style build-id
cache it falls back to use it. (IOW, it is backward compatible)

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160528151537.16098.85815.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1df6092..09c5c34 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1704,10 +1704,7 @@
 	}
 
 	/* Finally, find a cache of kallsyms */
-	scnprintf(path, sizeof(path), "%s/%s/%s",
-		  buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
-
-	if (access(path, F_OK)) {
+	if (!build_id_cache__kallsyms_path(sbuild_id, path, sizeof(path))) {
 		pr_err("No kallsyms or vmlinux with build-id %s was found\n",
 		       sbuild_id);
 		return NULL;