[Intel-gfx] [PATCH 3/4] drm/i915/gt: Protect execlists_hold/unhold from new waiters

[Chris Wilson]

As we may add new waiters to a request as it is being run, we need to
mark the list iteration as being safe for concurrent addition.

Fixes: 32ff621fd744 ("drm/i915/gt: Allow temporary suspension of inflight requests")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index b350e01d86d2..354a5d245cee 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -2378,7 +2378,7 @@ static void __execlists_hold(struct i915_request *rq)
 		list_move_tail(&rq->sched.link, &rq->engine->active.hold);
 		i915_request_set_hold(rq);
 
-		list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+		for_each_waiter(p, rq) {
 			struct i915_request *w =
 				container_of(p->waiter, typeof(*w), sched);
 
@@ -2496,7 +2496,7 @@ static void __execlists_unhold(struct i915_request *rq)
 		RQ_TRACE(rq, "hold release\n");
 
 		/* Also release any children on this engine that are ready */
-		list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+		for_each_waiter(p, rq) {
 			struct i915_request *w =
 				container_of(p->waiter, typeof(*w), sched);
 
-- 
2.25.0