From fec5cbad4a77d680da5ebb7b0dfd49b737dcc47f Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Tue, 13 Dec 2016 18:48:21 +0200 Subject: lib/debugfs: Check if debufs is already mounted before attempting to mount it MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit mount("/sys/kernel/debug") will return an error if something is already mounted there. So let's check for that before calling mount(). This allows many of the tools (eg. intel_reg) to work even when no drm drivers are loaded since the earlier "/sys/kernel/debug/dri" & co. path checks will fail in that case and we will fall back to attempting to mount debugfs ourselves. Signed-off-by: Ville Syrjälä --- lib/igt_debugfs.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'lib/igt_debugfs.c') diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c index f8c87275..d828687a 100644 --- a/lib/igt_debugfs.c +++ b/lib/igt_debugfs.c @@ -89,6 +89,22 @@ typedef struct { char dri_path[128]; } igt_debugfs_t; +static bool is_mountpoint(const char *path) +{ + char buf[strlen(path) + 4]; + dev_t dot_dev, dotdot_dev; + struct stat st; + + igt_assert_lt(snprintf(buf, sizeof(buf), "%s/.", path), sizeof(buf)); + igt_assert_eq(stat(buf, &st), 0); + dot_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; + + return dot_dev != dotdot_dev; +} /** * igt_debugfs_mount: @@ -109,8 +125,9 @@ const char *igt_debugfs_mount(void) if (stat("/sys/kernel/debug/dri", &st) == 0) return "/sys/kernel/debug"; - igt_assert(stat("/sys/kernel/debug", &st) == 0); - igt_assert(mount("debug", "/sys/kernel/debug", "debugfs", 0, 0) == 0); + igt_assert(is_mountpoint("/sys/kernel/debug") || + mount("debug", "/sys/kernel/debug", "debugfs", 0, 0) == 0); + return "/sys/kernel/debug"; } -- cgit v1.2.3