drm/tests: shmem: Hold reservation lock around purge

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

[   58.709128] WARNING: CPU: 1 PID: 1354 at drivers/gpu/drm/drm_gem_shmem_helper.c:515 drm_gem_shmem_purge_locked+0x51c/0x740

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

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 954907f7147d ("drm/shmem-helper: Refactor locked/unlocked functions")
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/20251212160317.287409-6-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index d377802b9dfdc1f3f289ec82c461b9feed2fa69a..de73c8ab8cca83e440b8fb49d72afa3d045c88da 100644 (file)
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -947,6 +947,21 @@ int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
        return ret;
 }
 EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_madvise);
+
+int drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
+{
+       struct drm_gem_object *obj = &shmem->base;
+       int ret;
+
+       ret = dma_resv_lock_interruptible(obj->resv, NULL);
+       if (ret)
+               return ret;
+       drm_gem_shmem_purge_locked(shmem);
+       dma_resv_unlock(obj->resv);
+
+       return 0;
+}
+EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_purge);
 #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 d639848e3c8ea6af002e5d2160396ee3d3512e6b..4b459f21acfd95d9e943da73fee6925c4e728fa7 100644 (file)
--- a/drivers/gpu/drm/tests/drm_gem_shmem_test.c
+++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c
@@ -340,7 +340,9 @@ static void drm_gem_shmem_test_purge(struct kunit *test)
        ret = drm_gem_shmem_is_purgeable(shmem);
        KUNIT_EXPECT_TRUE(test, ret);
 
-       drm_gem_shmem_purge_locked(shmem);
+       ret = drm_gem_shmem_purge(shmem);
+       KUNIT_ASSERT_EQ(test, ret, 0);
+
        KUNIT_EXPECT_NULL(test, shmem->pages);
        KUNIT_EXPECT_NULL(test, shmem->sgt);
        KUNIT_EXPECT_EQ(test, shmem->madv, -1);

diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index dd9a7c67195ea79ac242f9bd14e1e349574431a7..5ccdae21b94a97fe5e5b442f1a8ec8554f747a50 100644 (file)
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -308,6 +308,7 @@ struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev,
 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);
+int drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem);
 #endif
 
 #endif /* __DRM_GEM_SHMEM_HELPER_H__ */