Commit 3b0a0579 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Allow asynchronous waits on the i915_active barriers 



Allow the caller to also wait upon the barriers stored in i915_active.

v2: Hook up i915_request_await_active(I915_ACTIVE_AWAIT_BARRIER) as well
for completeness, and avoid the lazy GEM_BUG_ON()!

v3: Pull flush_lazy_signals() under the active-ref protection as it too
walks the rbtree and so we must be careful that we do not free it as we
iterate.

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/20200406155840.1728-2-chris@chris-wilson.co.uk
parent 442dbc5c

drivers/gpu/drm/i915/i915_active.c

+63 −10
Original line number Diff line number Diff line
@@ -542,35 +542,88 @@ static int __await_active(struct i915_active_fence *active, 
	return 0;

}



struct wait_barrier {

	struct wait_queue_entry base;

	struct i915_active *ref;

};



static int

barrier_wake(wait_queue_entry_t *wq, unsigned int mode, int flags, void *key)

{

	struct wait_barrier *wb = container_of(wq, typeof(*wb), base);



	if (i915_active_is_idle(wb->ref)) {

		list_del(&wq->entry);

		i915_sw_fence_complete(wq->private);

		kfree(wq);

	}



	return 0;

}



static int __await_barrier(struct i915_active *ref, struct i915_sw_fence *fence)

{

	struct wait_barrier *wb;



	wb = kmalloc(sizeof(*wb), GFP_KERNEL);

	if (unlikely(!wb))

		return -ENOMEM;



	GEM_BUG_ON(i915_active_is_idle(ref));

	if (!i915_sw_fence_await(fence)) {

		kfree(wb);

		return -EINVAL;

	}



	wb->base.flags = 0;

	wb->base.func = barrier_wake;

	wb->base.private = fence;

	wb->ref = ref;



	add_wait_queue(__var_waitqueue(ref), &wb->base);

	return 0;

}



static int await_active(struct i915_active *ref,

			unsigned int flags,

			int (*fn)(void *arg, struct dma_fence *fence),

			void *arg)

			void *arg, struct i915_sw_fence *barrier)

{

	int err = 0;



	if (!i915_active_acquire_if_busy(ref))

		return 0;



	if (flags & I915_ACTIVE_AWAIT_EXCL &&

	    rcu_access_pointer(ref->excl.fence)) {

		err = __await_active(&ref->excl, fn, arg);

		if (err)

			return err;

			goto out;

	}



	if (flags & I915_ACTIVE_AWAIT_ACTIVE &&

	    i915_active_acquire_if_busy(ref)) {

	if (flags & I915_ACTIVE_AWAIT_ACTIVE) {

		struct active_node *it, *n;



		rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {

			err = __await_active(&it->base, fn, arg);

			if (err)

				break;

				goto out;

		}

		i915_active_release(ref);

	}



	if (flags & I915_ACTIVE_AWAIT_BARRIER) {

		err = flush_lazy_signals(ref);

		if (err)

			return err;

			goto out;



		err = __await_barrier(ref, barrier);

		if (err)

			goto out;

	}



	return 0;

out:

	i915_active_release(ref);

	return err;

}



static int rq_await_fence(void *arg, struct dma_fence *fence)
@@ -582,7 +635,7 @@ int i915_request_await_active(struct i915_request *rq, 
			      struct i915_active *ref,

			      unsigned int flags)

{

	return await_active(ref, flags, rq_await_fence, rq);

	return await_active(ref, flags, rq_await_fence, rq, &rq->submit);

}



static int sw_await_fence(void *arg, struct dma_fence *fence)
@@ -595,7 +648,7 @@ int i915_sw_fence_await_active(struct i915_sw_fence *fence, 
			       struct i915_active *ref,

			       unsigned int flags)

{

	return await_active(ref, flags, sw_await_fence, fence);

	return await_active(ref, flags, sw_await_fence, fence, fence);

}



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)

drivers/gpu/drm/i915/i915_active.h

+1 −0
Original line number Diff line number Diff line
@@ -195,6 +195,7 @@ int i915_request_await_active(struct i915_request *rq, 
			      unsigned int flags);

#define I915_ACTIVE_AWAIT_EXCL BIT(0)

#define I915_ACTIVE_AWAIT_ACTIVE BIT(1)

#define I915_ACTIVE_AWAIT_BARRIER BIT(2)



int i915_active_acquire(struct i915_active *ref);

bool i915_active_acquire_if_busy(struct i915_active *ref);

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