drm/i915/guc: Unwind context requests in reverse order

When unwinding requests on a reset context, if other requests in the
context are in the priority list the requests could be resubmitted out
of seqno order. Traverse the list of active requests in reverse and
append to the head of the priority list to fix this.

Fixes: eb5e7da736f3 ("drm/i915/guc: Reset implementation for new GuC interface")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-4-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index aff5dd247a887a82181f148fc0e91dae535e1030..0c1e6b465fba9d5175c8be453e646339a2af4f5a 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -806,9 +806,9 @@ __unwind_incomplete_requests(struct intel_context *ce)
 
        spin_lock_irqsave(&sched_engine->lock, flags);
        spin_lock(&ce->guc_active.lock);
-       list_for_each_entry_safe(rq, rn,
-                                &ce->guc_active.requests,
-                                sched.link) {
+       list_for_each_entry_safe_reverse(rq, rn,
+                                        &ce->guc_active.requests,
+                                        sched.link) {
                if (i915_request_completed(rq))
                        continue;
 
@@ -825,7 +825,7 @@ __unwind_incomplete_requests(struct intel_context *ce)
                }
                GEM_BUG_ON(i915_sched_engine_is_empty(sched_engine));
 
-               list_add_tail(&rq->sched.link, pl);
+               list_add(&rq->sched.link, pl);
                set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
 
                spin_lock(&ce->guc_active.lock);