[Intel-gfx] [igt RFC 1/3] lib/debugfs: Make is_mountpoint() non-fatal

[Chris Wilson]

is_mountpoint() asserts rather than report the error. Normally this
isn't a problem, except for atypical selftests.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 lib/igt_debugfs.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
index 60b29e3a..2bdcdee1 100644
--- a/lib/igt_debugfs.c
+++ b/lib/igt_debugfs.c
@@ -88,18 +88,26 @@
 static bool is_mountpoint(const char *path)
 {
 	char buf[strlen(path) + 4];
-	dev_t dot_dev, dotdot_dev;
 	struct stat st;
+	dev_t dev;
 
 	igt_assert_lt(snprintf(buf, sizeof(buf), "%s/.", path), sizeof(buf));
-	igt_assert_eq(stat(buf, &st), 0);
-	dot_dev = st.st_dev;
+	if (stat(buf, &st))
+		return false;
+
+	if (!S_ISDIR(st.st_mode))
+		return false;
+
+	dev = st.st_dev;
 
 	igt_assert_lt(snprintf(buf, sizeof(buf), "%s/..", path), sizeof(buf));
-	igt_assert_eq(stat(buf, &st), 0);
-	dotdot_dev = st.st_dev;
+	if (stat(buf, &st))
+		return false;
+
+	if (!S_ISDIR(st.st_mode))
+		return false;
 
-	return dot_dev != dotdot_dev;
+	return dev != st.st_dev;
 }
 
 /**
@@ -113,16 +121,14 @@ static bool is_mountpoint(const char *path)
  */
 const char *igt_debugfs_mount(void)
 {
-	struct stat st;
+	if (is_mountpoint("/sys/kernel/debug"))
+		return "/sys/kernel/debug";
 
-	if (stat("/debug/dri", &st) == 0)
+	if (is_mountpoint("/debug"))
 		return "/debug";
 
-	if (stat("/sys/kernel/debug/dri", &st) == 0)
-		return "/sys/kernel/debug";
-
-	igt_assert(is_mountpoint("/sys/kernel/debug") ||
-		   mount("debug", "/sys/kernel/debug", "debugfs", 0, 0) == 0);
+	if (mount("debug", "/sys/kernel/debug", "debugfs", 0, 0))
+		return NULL;
 
 	return "/sys/kernel/debug";
 }
@@ -155,6 +161,7 @@ char *igt_debugfs_path(int device, char *path, int pathlen)
 	}
 
 	debugfs_root = igt_debugfs_mount();
+	igt_assert(debugfs_root);
 
 	idx = minor(st.st_rdev);
 	snprintf(path, pathlen, "%s/dri/%d/name", debugfs_root, idx);
-- 
2.15.0.rc0