[Intel-gfx] [PATCH 1/2] drm/i915/selftests: Exercise invalidation of dmabuf import from shrinker

[Chris Wilson]

Check that we can invalidate an object created for an imported dmabuf
(i.e. that we release the obj->mm.pages, and so its associated mapping of
the dmabuf) under memory pressure invoking the shrinker for direct
reclaim.

This is using our mock_dmabuf as the exporter, so while we may miss
intricate lock dependencies of a real device, we should capture any and
all core dependencies.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
---
 .../gpu/drm/i915/selftests/i915_gem_dmabuf.c  | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
index a7055b12e53c..105eaeb09ca7 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
@@ -22,6 +22,8 @@
  *
  */
 
+#include <linux/sched/mm.h>
+
 #include "../i915_selftest.h"
 
 #include "mock_gem_device.h"
@@ -370,6 +372,73 @@ static int igt_dmabuf_export_kmap(void *arg)
 	return err;
 }
 
+static int igt_dmabuf_import_shrink(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct drm_i915_gem_object *obj;
+	struct dma_buf *dmabuf;
+	bool has_pages;
+	int err;
+
+	dmabuf = mock_dmabuf(1);
+	if (IS_ERR(dmabuf))
+		return PTR_ERR(dmabuf);
+
+	obj = to_intel_bo(i915_gem_prime_import(&i915->drm, dmabuf));
+	dma_buf_put(dmabuf);
+	if (IS_ERR(obj)) {
+		pr_err("i915_gem_prime_import failed with err=%d\n",
+		       (int)PTR_ERR(obj));
+		return PTR_ERR(obj);
+	}
+
+	if (obj->base.dev != &i915->drm) {
+		pr_err("i915_gem_prime_import created a non-i915 object!\n");
+		err = -EINVAL;
+		goto out_obj;
+	}
+
+	if (obj->base.size != PAGE_SIZE) {
+		pr_err("i915_gem_prime_import is wrong size found %lld, expected %ld\n",
+		       (long long)obj->base.size, PAGE_SIZE);
+		err = -EINVAL;
+		goto out_obj;
+	}
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err)
+		goto out_obj;
+
+	i915_gem_object_unpin_pages(obj);
+
+	if (!i915_gem_object_has_pages(obj)) {
+		pr_err("Failed to acquire dma-buf pages\n");
+		err = -EINVAL;
+		goto out_obj;
+	}
+
+	/* Fake the shrinker invocation for direct-reclaim */
+	fs_reclaim_acquire(GFP_KERNEL);
+	i915_gem_shrink_all(i915);
+	fs_reclaim_release(GFP_KERNEL);
+
+	has_pages = i915_gem_object_has_pages(obj);
+	if (has_pages == i915_gem_object_is_shrinkable(obj)) {
+		if (has_pages)
+			pr_err("Failed to release dma-buf from shrinker!\n");
+		else
+			pr_err("Released unshrinkable dma-buf from shrinker!\n");
+
+		err = -EINVAL;
+		goto out_obj;
+	}
+
+	err = 0;
+out_obj:
+	i915_gem_object_put(obj);
+	return err;
+}
+
 int i915_gem_dmabuf_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
@@ -397,6 +466,7 @@ int i915_gem_dmabuf_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(igt_dmabuf_export),
+		SUBTEST(igt_dmabuf_import_shrink),
 	};
 
 	return i915_subtests(tests, i915);
-- 
2.18.0