gem_reg_read: Only check errno after a definite error

As upon success, errno is invalid and may give spurious false results.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65157
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 11 insertions, 18 deletions

diff --git a/tests/gem_reg_read.c b/tests/gem_reg_read.c
index 692dd987..743beac8 100644
--- a/tests/gem_reg_read.c
+++ b/tests/gem_reg_read.c
@@ -37,11 +37,11 @@ struct local_drm_i915_reg_read {
 
 #define REG_READ_IOCTL DRM_IOWR(DRM_COMMAND_BASE + 0x31, struct local_drm_i915_reg_read)
 
-static void handle_bad(int ret, int lerrno, int expected, const char *desc)
+static void handle_bad(int ret, int expected, const char *desc)
 {
-	if (ret != 0 && lerrno != expected) {
+	if (ret != 0 && errno != expected) {
 		fprintf(stderr, "%s - errno was %d, but should have been %d\n",
-				desc, lerrno, expected);
+				desc, errno, expected);
 		exit(EXIT_FAILURE);
 	} else if (ret == 0) {
 		fprintf(stderr, "%s - Command succeeded, but should have failed\n",
@@ -53,11 +53,9 @@ static void handle_bad(int ret, int lerrno, int expected, const char *desc)
 static uint64_t timer_query(int fd)
 {
 	struct local_drm_i915_reg_read reg_read;
-	int ret;
 
 	reg_read.offset = 0x2358;
-	ret = drmIoctl(fd, REG_READ_IOCTL, &reg_read);
-	if (ret) {
+	if (drmIoctl(fd, REG_READ_IOCTL, &reg_read)) {
 		perror("positive test case failed: ");
 		exit(EXIT_FAILURE);
 	}
@@ -68,31 +66,26 @@ static uint64_t timer_query(int fd)
 int main(int argc, char *argv[])
 {
 	struct local_drm_i915_reg_read reg_read;
-	int ret, fd;
-	uint64_t val;
+	int fd;
 
 	fd = drm_open_any();
 
 	reg_read.offset = 0x2358;
-	ret = drmIoctl(fd, REG_READ_IOCTL, &reg_read);
-	if (errno == EINVAL)
-		exit(77);
-	else if (ret)
-		exit(EXIT_FAILURE);
+	if (drmIoctl(fd, REG_READ_IOCTL, &reg_read))
+		exit(errno == EINVAL ? 77 : EXIT_FAILURE);
 
-	val = timer_query(fd);
+	reg_read.val = timer_query(fd);
 	sleep(1);
-	if (timer_query(fd) == val) {
+	if (timer_query(fd) == reg_read.val) {
 		fprintf(stderr, "Timer isn't moving, probably busted\n");
 		exit(EXIT_FAILURE);
 	}
 
 	/* bad reg */
 	reg_read.offset = 0x12345678;
-	ret = drmIoctl(fd, REG_READ_IOCTL, &reg_read);
-	handle_bad(ret, errno, EINVAL, "bad register");
+	handle_bad(drmIoctl(fd, REG_READ_IOCTL, &reg_read),
+		   EINVAL, "bad register");
 
 	close(fd);
-
 	exit(EXIT_SUCCESS);
 }