drm/tests: shmem: Add clean-up action to unpin pages

[ Upstream commit b47b9ec ]

Automatically unpin pages on cleanup. The test currently fails with
the error

[   58.246263] drm-kunit-mock-device drm_gem_shmem_test_get_sg_table.drm-kunit-mock-device: [drm] drm_WARN_ON(refcount_read(&shmem->pages_pin_count))

while cleaning up the GEM object. The pin count has to be zero at this
point.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: d586b53 ("drm/shmem-helper: Add and use pages_pin_count")
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v6.16+
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20251212160317.287409-3-tzimmermann@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: tdz

drivers/gpu/drm/tests/drm_gem_shmem_test.c

@@ -34,6 +34,9 @@ KUNIT_DEFINE_ACTION_WRAPPER(sg_free_table_wrapper, sg_free_table,
 KUNIT_DEFINE_ACTION_WRAPPER(drm_gem_shmem_free_wrapper, drm_gem_shmem_free,
 			    struct drm_gem_shmem_object *);
 
+KUNIT_DEFINE_ACTION_WRAPPER(drm_gem_shmem_unpin_wrapper, drm_gem_shmem_unpin,
+			    struct drm_gem_shmem_object *);
+
 /*
  * Test creating a shmem GEM object backed by shmem buffer. The test
  * case succeeds if the GEM object is successfully allocated with the
@@ -212,6 +215,9 @@ static void drm_gem_shmem_test_get_sg_table(struct kunit *test)
 	ret = drm_gem_shmem_pin(shmem);
 	KUNIT_ASSERT_EQ(test, ret, 0);
 
+	ret = kunit_add_action_or_reset(test, drm_gem_shmem_unpin_wrapper, shmem);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
 	sgt = drm_gem_shmem_get_sg_table(shmem);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, sgt);
 	KUNIT_EXPECT_NULL(test, shmem->sgt);