Give the barrier pool its own mutex to avoid a deadlock with transfer workers.

Author: DarioSamo

servers/rendering/rendering_device.cpp

@@ -5272,14 +5272,13 @@ void RenderingDevice::_wait_for_transfer_worker(TransferWorker *p_transfer_worke
 		p_transfer_worker->operations_processed = p_transfer_worker->operations_submitted;
 	}
 
-	if (!p_transfer_worker->texture_barriers.is_empty()) {
-		MutexLock transfer_worker_lock(transfer_worker_pool_mutex);
-		_flush_barriers_for_transfer_worker(p_transfer_worker);
-	}
+	_flush_barriers_for_transfer_worker(p_transfer_worker);
 }
 
 void RenderingDevice::_flush_barriers_for_transfer_worker(TransferWorker *p_transfer_worker) {
+	// Caller must have already acquired the mutex for the worker.
 	if (!p_transfer_worker->texture_barriers.is_empty()) {
+		MutexLock transfer_worker_lock(transfer_worker_pool_texture_barriers_mutex);
 		for (uint32_t i = 0; i < p_transfer_worker->texture_barriers.size(); i++) {
 			transfer_worker_pool_texture_barriers.push_back(p_transfer_worker->texture_barriers[i]);
 		}
@@ -5352,8 +5351,11 @@ void RenderingDevice::_submit_transfer_workers(RDD::CommandBufferID p_draw_comma
 			}
 		}
 	}
+}
 
-	if (p_draw_command_buffer && !transfer_worker_pool_texture_barriers.is_empty()) {
+void RenderingDevice::_submit_transfer_barriers(RDD::CommandBufferID p_draw_command_buffer) {
+	MutexLock transfer_worker_lock(transfer_worker_pool_texture_barriers_mutex);
+	if (!transfer_worker_pool_texture_barriers.is_empty()) {
 		driver->command_pipeline_barrier(p_draw_command_buffer, RDD::PIPELINE_STAGE_COPY_BIT, RDD::PIPELINE_STAGE_ALL_COMMANDS_BIT, {}, {}, transfer_worker_pool_texture_barriers);
 		transfer_worker_pool_texture_barriers.clear();
 	}
@@ -5953,6 +5955,7 @@ void RenderingDevice::_end_frame() {
 	// The command buffer must be copied into a stack variable as the driver workarounds can change the command buffer in use.
 	RDD::CommandBufferID command_buffer = frames[frame].command_buffer;
 	_submit_transfer_workers(command_buffer);
+	_submit_transfer_barriers(command_buffer);
 
 	draw_graph.end(RENDER_GRAPH_REORDER, RENDER_GRAPH_FULL_BARRIERS, command_buffer, frames[frame].command_buffer_pool);
 	driver->command_buffer_end(command_buffer);

servers/rendering/rendering_device.h

@@ -1285,6 +1285,7 @@ class RenderingDevice : public RenderingDeviceCommons {
 	LocalVector<uint32_t> transfer_worker_pool_available_list;
 	LocalVector<RDD::TextureBarrier> transfer_worker_pool_texture_barriers;
 	BinaryMutex transfer_worker_pool_mutex;
+	BinaryMutex transfer_worker_pool_texture_barriers_mutex;
 	ConditionVariable transfer_worker_pool_condition;
 
 	TransferWorker *_acquire_transfer_worker(uint32_t p_transfer_size, uint32_t p_required_align, uint32_t &r_staging_offset);
@@ -1299,6 +1300,7 @@ class RenderingDevice : public RenderingDeviceCommons {
 	void _check_transfer_worker_vertex_array(VertexArray *p_vertex_array);
 	void _check_transfer_worker_index_array(IndexArray *p_index_array);
 	void _submit_transfer_workers(RDD::CommandBufferID p_draw_command_buffer = RDD::CommandBufferID());
+	void _submit_transfer_barriers(RDD::CommandBufferID p_draw_command_buffer);
 	void _wait_for_transfer_workers();
 	void _free_transfer_workers();