[PATCH v2] i915/selftest/igt_mmap: let mmap tests run in kthread

[Mikolaj Wasiak]

When the driver is loaded on the system with numa nodes it might be run in
a kthread, which makes it impossible to use current->mm in the selftest.
This patch allows the selftest to use current->mm by using active_mm.

Signed-off-by: Mikolaj Wasiak <mikolaj.was...@intel.com>
Reviewed-by: Eugene Kobyak <eugene.kob...@intel.com>
---
v1 -> v2: Simplify logic of enabling and disabling active_mm

 drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c 
b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index 804f74084bd4..9c3f17e51885 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -1837,6 +1837,8 @@ static int igt_mmap_revoke(void *arg)
 
 int i915_gem_mman_live_selftests(struct drm_i915_private *i915)
 {
+       int ret;
+       bool unuse_mm = false;
        static const struct i915_subtest tests[] = {
                SUBTEST(igt_partial_tiling),
                SUBTEST(igt_smoke_tiling),
@@ -1848,5 +1850,15 @@ int i915_gem_mman_live_selftests(struct drm_i915_private 
*i915)
                SUBTEST(igt_mmap_gpu),
        };
 
-       return i915_live_subtests(tests, i915);
+       if (!current->mm) {
+               kthread_use_mm(current->active_mm);
+               unuse_mm = true;
+       }
+
+       ret = i915_live_subtests(tests, i915);
+
+       if (unuse_mm)
+               kthread_unuse_mm(current->active_mm);
+
+       return ret;
 }
-- 
2.43.0