perf trace: Clean up find_debugfs()

Remove redundant code for 'perf trace'

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <4B3870DE.7090500@cn.fujitsu.com>
[ v2: resolved conflicts with recent changes ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/debugfs.c

@@ -130,6 +130,7 @@ char *debugfs_mount(const char *mountpoint)
 
 	/* save the mountpoint */
 	strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
+	debugfs_found = 1;
 
 	return debugfs_mountpoint;
 }

tools/perf/util/trace-event-info.c

@@ -38,6 +38,7 @@
 
 #include "../perf.h"
 #include "trace-event.h"
+#include "debugfs.h"
 
 #define VERSION "0.5"
 
@@ -102,32 +103,12 @@ void *malloc_or_die(unsigned int size)
 
 static const char *find_debugfs(void)
 {
-	static char debugfs[MAX_PATH+1];
+	const char *path = debugfs_mount(NULL);
-	static int debugfs_found;
-	FILE *fp;
-	struct mntent *m;
 
-	if (debugfs_found)
+	if (!path)
-		return debugfs;
+		die("Your kernel not support debugfs filesystem");
 
-	fp = setmntent("/proc/mounts", "r");
+	return path;
-	if (!fp)
-		die("Can't open /proc/mounts for read");
-
-	while ((m = getmntent(fp)) != NULL) {
-		if (strcmp(m->mnt_type, "debugfs") == 0) {
-			strcpy(debugfs, m->mnt_dir);
-			debugfs_found = 1;
-			break;
-		}
-	}
-
-	endmntent(fp);
-
-	if (!debugfs_found)
-		die("debugfs not mounted, please mount");
-
-	return debugfs;
 }
 
 /*