[18/20] drm/i915/selftests: Fix locking inversion in lrc selftest.

Commit Message

Maarten Lankhorst Feb. 25, 2020, 2:38 p.m. UTC

This function does not use intel_context_create_request, so it has
to use the same locking order as normal code. This is required to
shut up lockdep in selftests.

Signed-off-by: Maarten Lankhorst <[e-mail]>
---
 drivers/gpu/drm/i915/gt/selftest_lrc.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index febd608c23a7..d312b847172b 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -4226,6 +4226,7 @@  static int __live_lrc_state(struct intel_engine_cs *engine,
 {
 	struct intel_context *ce;
 	struct i915_request *rq;
+	struct i915_gem_ww_ctx ww;
 	enum {
 		RING_START_IDX = 0,
 		RING_TAIL_IDX,
@@ -4240,7 +4241,11 @@  static int __live_lrc_state(struct intel_engine_cs *engine,
 	if (IS_ERR(ce))
 		return PTR_ERR(ce);
 
-	err = intel_context_pin(ce);
+	i915_gem_ww_ctx_init(&ww, false);
+retry:
+	err = i915_gem_object_lock(scratch->obj, &ww);
+	if (!err)
+		err = intel_context_pin_ww(ce, &ww);
 	if (err)
 		goto err_put;
 
@@ -4269,11 +4274,9 @@  static int __live_lrc_state(struct intel_engine_cs *engine,
 	*cs++ = i915_ggtt_offset(scratch) + RING_TAIL_IDX * sizeof(u32);
 	*cs++ = 0;
 
-	i915_vma_lock(scratch);
 	err = i915_request_await_object(rq, scratch->obj, true);
 	if (!err)
 		err = i915_vma_move_to_active(scratch, rq, EXEC_OBJECT_WRITE);
-	i915_vma_unlock(scratch);
 
 	i915_request_get(rq);
 	i915_request_add(rq);
@@ -4310,6 +4313,12 @@  static int __live_lrc_state(struct intel_engine_cs *engine,
 err_unpin:
 	intel_context_unpin(ce);
 err_put:
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
 	intel_context_put(ce);
 	return err;
 }