drm/i915: Move i915_vma_lock in the selftests to avoid lock inversion, v3.

Make sure vma_lock is not used as inner lock when kernel context is used,
and add ww handling where appropriate.

Ensure that execbuf selftests keep passing by using ww handling.

Changes since v2:
- Fix i915_gem_context finally.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819140904.1708856-22-maarten.lankhorst@linux.intel.com
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

1 files changed, 50 insertions, 56 deletions

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index fa40006b453a..99becb86abd3 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -893,24 +893,15 @@ out_file:
 	return err;
 }
 
-static struct i915_vma *rpcs_query_batch(struct i915_vma *vma)
+static int rpcs_query_batch(struct drm_i915_gem_object *rpcs, struct i915_vma *vma)
 {
-	struct drm_i915_gem_object *obj;
 	u32 *cmd;
-	int err;
 
-	if (INTEL_GEN(vma->vm->i915) < 8)
-		return ERR_PTR(-EINVAL);
+	GEM_BUG_ON(INTEL_GEN(vma->vm->i915) < 8);
 
-	obj = i915_gem_object_create_internal(vma->vm->i915, PAGE_SIZE);
-	if (IS_ERR(obj))
-		return ERR_CAST(obj);
-
-	cmd = i915_gem_object_pin_map(obj, I915_MAP_WB);
-	if (IS_ERR(cmd)) {
-		err = PTR_ERR(cmd);
-		goto err;
-	}
+	cmd = i915_gem_object_pin_map(rpcs, I915_MAP_WB);
+	if (IS_ERR(cmd))
+		return PTR_ERR(cmd);
 
 	*cmd++ = MI_STORE_REGISTER_MEM_GEN8;
 	*cmd++ = i915_mmio_reg_offset(GEN8_R_PWR_CLK_STATE);
@@ -918,26 +909,12 @@ static struct i915_vma *rpcs_query_batch(struct i915_vma *vma)
 	*cmd++ = upper_32_bits(vma->node.start);
 	*cmd = MI_BATCH_BUFFER_END;
 
-	__i915_gem_object_flush_map(obj, 0, 64);
-	i915_gem_object_unpin_map(obj);
+	__i915_gem_object_flush_map(rpcs, 0, 64);
+	i915_gem_object_unpin_map(rpcs);
 
 	intel_gt_chipset_flush(vma->vm->gt);
 
-	vma = i915_vma_instance(obj, vma->vm, NULL);
-	if (IS_ERR(vma)) {
-		err = PTR_ERR(vma);
-		goto err;
-	}
-
-	err = i915_vma_pin(vma, 0, 0, PIN_USER);
-	if (err)
-		goto err;
-
-	return vma;
-
-err:
-	i915_gem_object_put(obj);
-	return ERR_PTR(err);
+	return 0;
 }
 
 static int
@@ -945,52 +922,68 @@ emit_rpcs_query(struct drm_i915_gem_object *obj,
 		struct intel_context *ce,
 		struct i915_request **rq_out)
 {
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_request *rq;
+	struct i915_gem_ww_ctx ww;
 	struct i915_vma *batch;
 	struct i915_vma *vma;
+	struct drm_i915_gem_object *rpcs;
 	int err;
 
 	GEM_BUG_ON(!intel_engine_can_store_dword(ce->engine));
 
+	if (INTEL_GEN(i915) < 8)
+		return -EINVAL;
+
 	vma = i915_vma_instance(obj, ce->vm, NULL);
 	if (IS_ERR(vma))
 		return PTR_ERR(vma);
 
-	i915_gem_object_lock(obj, NULL);
-	err = i915_gem_object_set_to_gtt_domain(obj, false);
-	i915_gem_object_unlock(obj);
-	if (err)
-		return err;
+	rpcs = i915_gem_object_create_internal(i915, PAGE_SIZE);
+	if (IS_ERR(rpcs))
+		return PTR_ERR(rpcs);
 
-	err = i915_vma_pin(vma, 0, 0, PIN_USER);
-	if (err)
-		return err;
-
-	batch = rpcs_query_batch(vma);
+	batch = i915_vma_instance(rpcs, ce->vm, NULL);
 	if (IS_ERR(batch)) {
 		err = PTR_ERR(batch);
-		goto err_vma;
+		goto err_put;
 	}
 
+	i915_gem_ww_ctx_init(&ww, false);
+retry:
+	err = i915_gem_object_lock(obj, &ww);
+	if (!err)
+		err = i915_gem_object_lock(rpcs, &ww);
+	if (!err)
+		err = i915_gem_object_set_to_gtt_domain(obj, false);
+	if (!err)
+		err = i915_vma_pin_ww(vma, &ww, 0, 0, PIN_USER);
+	if (err)
+		goto err_put;
+
+	err = i915_vma_pin_ww(batch, &ww, 0, 0, PIN_USER);
+	if (err)
+		goto err_vma;
+
+	err = rpcs_query_batch(rpcs, vma);
+	if (err)
+		goto err_batch;
+
 	rq = i915_request_create(ce);
 	if (IS_ERR(rq)) {
 		err = PTR_ERR(rq);
 		goto err_batch;
 	}
 
-	i915_vma_lock(batch);
 	err = i915_request_await_object(rq, batch->obj, false);
 	if (err == 0)
 		err = i915_vma_move_to_active(batch, rq, 0);
-	i915_vma_unlock(batch);
 	if (err)
 		goto skip_request;
 
-	i915_vma_lock(vma);
 	err = i915_request_await_object(rq, vma->obj, true);
 	if (err == 0)
 		err = i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
-	i915_vma_unlock(vma);
 	if (err)
 		goto skip_request;
 
@@ -1006,23 +999,24 @@ emit_rpcs_query(struct drm_i915_gem_object *obj,
 	if (err)
 		goto skip_request;
 
-	i915_vma_unpin_and_release(&batch, 0);
-	i915_vma_unpin(vma);
-
 	*rq_out = i915_request_get(rq);
 
-	i915_request_add(rq);
-
-	return 0;
-
 skip_request:
-	i915_request_set_error_once(rq, err);
+	if (err)
+		i915_request_set_error_once(rq, err);
 	i915_request_add(rq);
 err_batch:
-	i915_vma_unpin_and_release(&batch, 0);
+	i915_vma_unpin(batch);
 err_vma:
 	i915_vma_unpin(vma);
-
+err_put:
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	i915_gem_object_put(rpcs);
 	return err;
 }