Commit 340c4c8d authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Add to timeline requires the timeline mutex 



Modifying a remote context requires careful serialisation with requests
on that context, and that serialisation requires us to take their
timeline->mutex. Make it so.

Note that while struct_mutex rules, we can't create more than one
request in parallel, but that age is soon coming to an end.

v2: Though it doesn't affect the current users, contexts may share
timelines so check if we already hold the right mutex.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190725131447.27515-1-chris@chris-wilson.co.uk
parent f91bf738

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

+18 −5
Original line number Diff line number Diff line
@@ -254,11 +254,19 @@ int intel_context_prepare_remote_request(struct intel_context *ce, 
	/* Only suitable for use in remotely modifying this context */

	GEM_BUG_ON(rq->hw_context == ce);



	/* Queue this switch after all other activity by this context. */

	err = i915_active_request_set(&tl->last_request, rq);

	if (rq->timeline != tl) { /* beware timeline sharing */

		err = mutex_lock_interruptible_nested(&tl->mutex,

						      SINGLE_DEPTH_NESTING);

		if (err)

			return err;



		/* Queue this switch after current activity by this context. */

		err = i915_active_request_set(&tl->last_request, rq);

		if (err)

			goto unlock;

	}

	lockdep_assert_held(&tl->mutex);



	/*

	 * Guarantee context image and the timeline remains pinned until the

	 * modifying request is retired by setting the ce activity tracker.
@@ -267,7 +275,12 @@ int intel_context_prepare_remote_request(struct intel_context *ce, 
	 * words transfer the pinned ce object to tracked active request.

	 */

	GEM_BUG_ON(i915_active_is_idle(&ce->active));

	return i915_active_ref(&ce->active, rq->fence.context, rq);

	err = i915_active_ref(&ce->active, rq->fence.context, rq);



unlock:

	if (rq->timeline != tl)

		mutex_unlock(&tl->mutex);

	return err;

}



struct i915_request *intel_context_create_request(struct intel_context *ce)