drm/i915/gt: Cancel submitted requests upon context reset

Since we process schedule-in of a context after submitting the request,
if we decide to reset the context at that time, we also have to cancel
the requets we have marked for submission.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201230220028.17089-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_execlists_submission.c

@@ -215,22 +215,32 @@ static void mark_eio(struct i915_request *rq)
 }
 
 static struct i915_request *
-active_request(const struct intel_timeline * const tl, struct i915_request *rq)
+__active_request(const struct intel_timeline * const tl,
+		 struct i915_request *rq,
+		 int error)
 {
 	struct i915_request *active = rq;
 
-	rcu_read_lock();
-	list_for_each_entry_continue_reverse(rq, &tl->requests, link) {
+	list_for_each_entry_from_reverse(rq, &tl->requests, link) {
 		if (__i915_request_is_complete(rq))
 			break;
 
+		if (error) {
+			i915_request_set_error_once(rq, error);
+			__i915_request_skip(rq);
+		}
 		active = rq;
 	}
-	rcu_read_unlock();
 
 	return active;
 }
 
+static struct i915_request *
+active_request(const struct intel_timeline * const tl, struct i915_request *rq)
+{
+	return __active_request(tl, rq, 0);
+}
+
 static inline void
 ring_set_paused(const struct intel_engine_cs *engine, int state)
 {
@@ -487,14 +497,14 @@ static void reset_active(struct i915_request *rq,
 	 * remain correctly ordered. And we defer to __i915_request_submit()
 	 * so that all asynchronous waits are correctly handled.
 	 */
-	ENGINE_TRACE(engine, "{ rq=%llx:%lld }\n",
+	ENGINE_TRACE(engine, "{ reset rq=%llx:%lld }\n",
 		     rq->fence.context, rq->fence.seqno);
 
 	/* On resubmission of the active request, payload will be scrubbed */
 	if (__i915_request_is_complete(rq))
 		head = rq->tail;
 	else
-		head = active_request(ce->timeline, rq)->head;
+		head = __active_request(ce->timeline, rq, -EIO)->head;
 	head = intel_ring_wrap(ce->ring, head);
 
 	/* Scrub the context image to prevent replaying the previous batch */

drivers/gpu/drm/i915/i915_request.c

@@ -490,6 +490,8 @@ void __i915_request_skip(struct i915_request *rq)
 	if (rq->infix == rq->postfix)
 		return;
 
+	RQ_TRACE(rq, "error: %d\n", rq->fence.error);
+
 	/*
 	 * As this request likely depends on state from the lost
 	 * context, clear out all the user operations leaving the