perf_counter: log full path names

Impact: fix perf-report output for /home mounted binaries, etc.

dentry_path() only provide path-names up to the mount root, which is
unsuited for out purpose, use d_path() instead.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090409085524.601794134@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/perf_counter.c

@@ -2116,7 +2116,7 @@ static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
 			name = strncpy(tmp, "//enomem", sizeof(tmp));
 			goto got_name;
 		}
-		name = dentry_path(file->f_dentry, buf, PATH_MAX);
+		name = d_path(&file->f_path, buf, PATH_MAX);
 		if (IS_ERR(name)) {
 			name = strncpy(tmp, "//toolong", sizeof(tmp));
 			goto got_name;