We can (and should) close the descriptor immediately after the import. Gets the following CTS test to pass without requiring to increase limits for open file descriptors: dEQP-VK.synchronization.basic.binary_semaphore.chain Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11105>