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>

3 files changed, 95 insertions, 78 deletions

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
index dcdfc396f2f8..7049a6bbc03d 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
@@ -201,25 +201,25 @@ static int gpu_set(struct context *ctx, unsigned long offset, u32 v)
 
 	i915_gem_object_lock(ctx->obj, NULL);
 	err = i915_gem_object_set_to_gtt_domain(ctx->obj, true);
-	i915_gem_object_unlock(ctx->obj);
 	if (err)
-		return err;
+		goto out_unlock;
 
 	vma = i915_gem_object_ggtt_pin(ctx->obj, NULL, 0, 0, 0);
-	if (IS_ERR(vma))
-		return PTR_ERR(vma);
+	if (IS_ERR(vma)) {
+		err = PTR_ERR(vma);
+		goto out_unlock;
+	}
 
 	rq = intel_engine_create_kernel_request(ctx->engine);
 	if (IS_ERR(rq)) {
-		i915_vma_unpin(vma);
-		return PTR_ERR(rq);
+		err = PTR_ERR(rq);
+		goto out_unpin;
 	}
 
 	cs = intel_ring_begin(rq, 4);
 	if (IS_ERR(cs)) {
-		i915_request_add(rq);
-		i915_vma_unpin(vma);
-		return PTR_ERR(cs);
+		err = PTR_ERR(cs);
+		goto out_rq;
 	}
 
 	if (INTEL_GEN(ctx->engine->i915) >= 8) {
@@ -240,14 +240,16 @@ static int gpu_set(struct context *ctx, unsigned long offset, u32 v)
 	}
 	intel_ring_advance(rq, cs);
 
-	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);
-	i915_vma_unpin(vma);
 
+out_rq:
 	i915_request_add(rq);
+out_unpin:
+	i915_vma_unpin(vma);
+out_unlock:
+	i915_gem_object_unlock(ctx->obj);
 
 	return err;
 }
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;
 }
 
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index 9fb95a45bcad..d27d87a678c8 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -528,31 +528,42 @@ static int make_obj_busy(struct drm_i915_gem_object *obj)
 	for_each_uabi_engine(engine, i915) {
 		struct i915_request *rq;
 		struct i915_vma *vma;
+		struct i915_gem_ww_ctx ww;
 		int err;
 
 		vma = i915_vma_instance(obj, &engine->gt->ggtt->vm, NULL);
 		if (IS_ERR(vma))
 			return PTR_ERR(vma);
 
-		err = i915_vma_pin(vma, 0, 0, PIN_USER);
+		i915_gem_ww_ctx_init(&ww, false);
+retry:
+		err = i915_gem_object_lock(obj, &ww);
+		if (!err)
+			err = i915_vma_pin_ww(vma, &ww, 0, 0, PIN_USER);
 		if (err)
-			return err;
+			goto err;
 
 		rq = intel_engine_create_kernel_request(engine);
 		if (IS_ERR(rq)) {
-			i915_vma_unpin(vma);
-			return PTR_ERR(rq);
+			err = PTR_ERR(rq);
+			goto err_unpin;
 		}
 
-		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);
 
 		i915_request_add(rq);
+err_unpin:
 		i915_vma_unpin(vma);
+err:
+		if (err == -EDEADLK) {
+			err = i915_gem_ww_ctx_backoff(&ww);
+			if (!err)
+				goto retry;
+		}
+		i915_gem_ww_ctx_fini(&ww);
 		if (err)
 			return err;
 	}
@@ -1123,6 +1134,7 @@ static int __igt_mmap_gpu(struct drm_i915_private *i915,
 	for_each_uabi_engine(engine, i915) {
 		struct i915_request *rq;
 		struct i915_vma *vma;
+		struct i915_gem_ww_ctx ww;
 
 		vma = i915_vma_instance(obj, engine->kernel_context->vm, NULL);
 		if (IS_ERR(vma)) {
@@ -1130,9 +1142,13 @@ static int __igt_mmap_gpu(struct drm_i915_private *i915,
 			goto out_unmap;
 		}
 
-		err = i915_vma_pin(vma, 0, 0, PIN_USER);
+		i915_gem_ww_ctx_init(&ww, false);
+retry:
+		err = i915_gem_object_lock(obj, &ww);
+		if (!err)
+			err = i915_vma_pin_ww(vma, &ww, 0, 0, PIN_USER);
 		if (err)
-			goto out_unmap;
+			goto out_ww;
 
 		rq = i915_request_create(engine->kernel_context);
 		if (IS_ERR(rq)) {
@@ -1140,11 +1156,9 @@ static int __igt_mmap_gpu(struct drm_i915_private *i915,
 			goto out_unpin;
 		}
 
-		i915_vma_lock(vma);
 		err = i915_request_await_object(rq, vma->obj, false);
 		if (err == 0)
 			err = i915_vma_move_to_active(vma, rq, 0);
-		i915_vma_unlock(vma);
 
 		err = engine->emit_bb_start(rq, vma->node.start, 0, 0);
 		i915_request_get(rq);
@@ -1166,6 +1180,13 @@ static int __igt_mmap_gpu(struct drm_i915_private *i915,
 
 out_unpin:
 		i915_vma_unpin(vma);
+out_ww:
+		if (err == -EDEADLK) {
+			err = i915_gem_ww_ctx_backoff(&ww);
+			if (!err)
+				goto retry;
+		}
+		i915_gem_ww_ctx_fini(&ww);
 		if (err)
 			goto out_unmap;
 	}