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path: root/drivers/gpu/drm/i915/i915_request.c
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Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.c')
-rw-r--r--drivers/gpu/drm/i915/i915_request.c41
1 files changed, 28 insertions, 13 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index f56b046a32de..dcaa85a91090 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -275,7 +275,7 @@ bool i915_request_retire(struct i915_request *rq)
spin_unlock_irq(&rq->lock);
remove_from_client(rq);
- list_del(&rq->link);
+ list_del_rcu(&rq->link);
intel_context_exit(rq->context);
intel_context_unpin(rq->context);
@@ -721,6 +721,8 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
rq->infix = rq->ring->emit; /* end of header; start of user payload */
intel_context_mark_active(ce);
+ list_add_tail_rcu(&rq->link, &tl->requests);
+
return rq;
err_unwind:
@@ -777,13 +779,23 @@ i915_request_await_start(struct i915_request *rq, struct i915_request *signal)
GEM_BUG_ON(i915_request_timeline(rq) ==
rcu_access_pointer(signal->timeline));
+ if (i915_request_started(signal))
+ return 0;
+
fence = NULL;
rcu_read_lock();
spin_lock_irq(&signal->lock);
- if (!i915_request_started(signal) &&
- !list_is_first(&signal->link,
- &rcu_dereference(signal->timeline)->requests)) {
- struct i915_request *prev = list_prev_entry(signal, link);
+ do {
+ struct list_head *pos = READ_ONCE(signal->link.prev);
+ struct i915_request *prev;
+
+ /* Confirm signal has not been retired, the link is valid */
+ if (unlikely(i915_request_started(signal)))
+ break;
+
+ /* Is signal the earliest request on its timeline? */
+ if (pos == &rcu_dereference(signal->timeline)->requests)
+ break;
/*
* Peek at the request before us in the timeline. That
@@ -791,13 +803,18 @@ i915_request_await_start(struct i915_request *rq, struct i915_request *signal)
* after acquiring a reference to it, confirm that it is
* still part of the signaler's timeline.
*/
- if (i915_request_get_rcu(prev)) {
- if (list_next_entry(prev, link) == signal)
- fence = &prev->fence;
- else
- i915_request_put(prev);
+ prev = list_entry(pos, typeof(*prev), link);
+ if (!i915_request_get_rcu(prev))
+ break;
+
+ /* After the strong barrier, confirm prev is still attached */
+ if (unlikely(READ_ONCE(prev->link.next) != &signal->link)) {
+ i915_request_put(prev);
+ break;
}
- }
+
+ fence = &prev->fence;
+ } while (0);
spin_unlock_irq(&signal->lock);
rcu_read_unlock();
if (!fence)
@@ -1242,8 +1259,6 @@ __i915_request_add_to_timeline(struct i915_request *rq)
0);
}
- list_add_tail(&rq->link, &timeline->requests);
-
/*
* Make sure that no request gazumped us - if it was allocated after
* our i915_request_alloc() and called __i915_request_add() before