[PATCH 6.19 522/844] drm/tests: shmem: Hold reservation lock around madvise

[Sasha Levin]

From: Thomas Zimmermann <tzimmermann@xxxxxxx>

[ Upstream commit 607d07d8cc0b835a8701259f08a03dc149b79b4f ]

Acquire and release the GEM object's reservation lock around calls
to the object's madvide operation. The tests use
drm_gem_shmem_madvise_locked(), which led to errors such as show below.

[   58.339389] WARNING: CPU: 1 PID: 1352 at drivers/gpu/drm/drm_gem_shmem_helper.c:499 drm_gem_shmem_madvise_locked+0xde/0x140

Only export the new helper drm_gem_shmem_madvise() for Kunit tests.
This is not an interface for regular drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Fixes: 954907f7147d ("drm/shmem-helper: Refactor locked/unlocked functions")
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v6.16+
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Link: https://patch.msgid.link/20251212160317.287409-5-tzimmermann@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c     | 15 +++++++++++++++
 drivers/gpu/drm/tests/drm_gem_shmem_test.c |  8 ++++----
 include/drm/drm_gem_shmem_helper.h         |  1 +
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index b7064b8333e89..1dfc9c4089587 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -925,6 +925,21 @@ void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, struct iosys_map *
 	dma_resv_unlock(obj->resv);
 }
 EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_vunmap);
+
+int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
+{
+	struct drm_gem_object *obj = &shmem->base;
+	int ret;
+
+	ret = dma_resv_lock_interruptible(obj->resv, NULL);
+	if (ret)
+		return ret;
+	ret = drm_gem_shmem_madvise_locked(shmem, madv);
+	dma_resv_unlock(obj->resv);
+
+	return ret;
+}
+EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_madvise);
 #endif
 
 MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
diff --git a/drivers/gpu/drm/tests/drm_gem_shmem_test.c b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
index 3e7c6f20fbcca..d639848e3c8ea 100644
--- a/drivers/gpu/drm/tests/drm_gem_shmem_test.c
+++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
@@ -292,17 +292,17 @@ static void drm_gem_shmem_test_madvise(struct kunit *test)
 	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
 	KUNIT_ASSERT_EQ(test, ret, 0);
 
-	ret = drm_gem_shmem_madvise_locked(shmem, 1);
+	ret = drm_gem_shmem_madvise(shmem, 1);
 	KUNIT_EXPECT_TRUE(test, ret);
 	KUNIT_ASSERT_EQ(test, shmem->madv, 1);
 
 	/* Set madv to a negative value */
-	ret = drm_gem_shmem_madvise_locked(shmem, -1);
+	ret = drm_gem_shmem_madvise(shmem, -1);
 	KUNIT_EXPECT_FALSE(test, ret);
 	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
 
 	/* Check that madv cannot be set back to a positive value */
-	ret = drm_gem_shmem_madvise_locked(shmem, 0);
+	ret = drm_gem_shmem_madvise(shmem, 0);
 	KUNIT_EXPECT_FALSE(test, ret);
 	KUNIT_ASSERT_EQ(test, shmem->madv, -1);
 }
@@ -330,7 +330,7 @@ static void drm_gem_shmem_test_purge(struct kunit *test)
 	ret = drm_gem_shmem_is_purgeable(shmem);
 	KUNIT_EXPECT_FALSE(test, ret);
 
-	ret = drm_gem_shmem_madvise_locked(shmem, 1);
+	ret = drm_gem_shmem_madvise(shmem, 1);
 	KUNIT_EXPECT_TRUE(test, ret);
 
 	/* The scatter/gather table will be freed by drm_gem_shmem_free */
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index 6924ee226655a..3dd93e2df7092 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -310,6 +310,7 @@ struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev,
 #if IS_ENABLED(CONFIG_KUNIT)
 int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map);
 void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map);
+int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv);
 #endif
 
 #endif /* __DRM_GEM_SHMEM_HELPER_H__ */
-- 
2.51.0