[igt-dev] [PATCH i-g-t v2 09/11] lib/kunit: Prepare for KTAP parsing after modprobe completed

[Janusz Krzysztofik]

We are going to add support for reading a list of kunit test cases
provided by a kunit test module prior to executing those test cases.  That
will be done by first loading kunit modules in list only mode, then
reading the list from /dev/kmsg with our KTAP parser.  Since that parsing
will be performed after the kunit test module is successfully loaded and
there will be no concurrently running modprobe thread, we need to make
synchronization of reads from /dev/kmsg with potential errors modprobe
thread optional.

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
---
 lib/igt_kmod.c | 50 ++++++++++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/lib/igt_kmod.c b/lib/igt_kmod.c
index fed0855c84..ed41aa1235 100644
--- a/lib/igt_kmod.c
+++ b/lib/igt_kmod.c
@@ -802,34 +802,36 @@ static int kunit_kmsg_result_get(struct igt_list_head *results,
 		if (igt_debug_on(igt_kernel_tainted(&taints)))
 			return -ENOTRECOVERABLE;
 
-		err = igt_debug_on(sigaction(SIGCHLD, &sigchld, saved));
-		if (err == -1)
-			return -errno;
-		else if (unlikely(err))
-			return err;
-
-		err = pthread_mutex_lock(&modprobe->lock);
-		switch (err) {
-		case EOWNERDEAD:
-			/* leave the mutex unrecoverable */
-			igt_debug_on(pthread_mutex_unlock(&modprobe->lock));
-			__attribute__ ((fallthrough));
-		case ENOTRECOVERABLE:
-			igt_debug_on(sigaction(SIGCHLD, saved, NULL));
-			if (igt_debug_on(modprobe->err))
-				return modprobe->err;
-			break;
-		case 0:
-			break;
-		default:
-			igt_debug("pthread_mutex_lock() error: %d\n", err);
-			igt_debug_on(sigaction(SIGCHLD, saved, NULL));
-			return -err;
+		if (modprobe) {
+			err = igt_debug_on(sigaction(SIGCHLD, &sigchld, saved));
+			if (err == -1)
+				return -errno;
+			else if (unlikely(err))
+				return err;
+
+			err = pthread_mutex_lock(&modprobe->lock);
+			switch (err) {
+			case EOWNERDEAD:
+				/* leave the mutex unrecoverable */
+				igt_debug_on(pthread_mutex_unlock(&modprobe->lock));
+				__attribute__ ((fallthrough));
+			case ENOTRECOVERABLE:
+				igt_debug_on(sigaction(SIGCHLD, saved, NULL));
+				if (igt_debug_on(modprobe->err))
+					return modprobe->err;
+				break;
+			case 0:
+				break;
+			default:
+				igt_debug("pthread_mutex_lock() error: %d\n", err);
+				igt_debug_on(sigaction(SIGCHLD, saved, NULL));
+				return -err;
+			}
 		}
 
 		ret = read(fd, record, BUF_LEN);
 
-		if (!err) {
+		if (modprobe && !err) {
 			igt_debug_on(pthread_mutex_unlock(&modprobe->lock));
 			igt_debug_on(sigaction(SIGCHLD, saved, NULL));
 		}
-- 
2.42.0