[PATCH i-g-t v2 2/3] lib/igt_kmod: Make sure errno is not already set before unbinding

[Daniele Ceraolo Spurio]

We assert that errno is zero after unbinding, so we need to make sure it
wasn't already non-zero beforehand or we might incorrectly fail.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
---
The non-zero starting errno hitting the assert is reproed when using
unbind in the 1915 reload-with-fault-injection test:
https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_12349/shard-snb5/igt@i915_module_load@reload-with-fault-injection.html

 lib/igt_kmod.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/igt_kmod.c b/lib/igt_kmod.c
index d73cb4101..a008b3c29 100644
--- a/lib/igt_kmod.c
+++ b/lib/igt_kmod.c
@@ -662,6 +662,8 @@ int igt_kmod_unbind(const char *mod_name)
 	int dirlen;
 	DIR *dir;
 
+	errno = 0;
+
 	dirlen = snprintf(path, sizeof(path), "/sys/module/%s/drivers/pci:%s/",
 			  mod_name, mod_name);
 	igt_assert(dirlen < sizeof(path));
-- 
2.43.0