virtio-blk: rename dataplane create/destroy functions

virtio-blk: rename dataplane create/destroy functions

virtio_blk_data_plane_create() and virtio_blk_data_plane_destroy() are
actually about s->vq_aio_context[] rather than managing
dataplane-specific state.

As a prerequisite to using s->vq_aio_context[] in all code paths (even
when dataplane is not used), rename these functions to reflect that they
just manage s->vq_aio_context and call them regardless of whether or not
dataplane is in use.

Note that virtio-blk supports running with -device
virtio-blk-pci,ioevent=off where the vCPU thread enters the device
emulation code. In this mode ioeventfd is not used for virtqueue
processing. However, we still want to initialize s->vq_aio_context[] to
qemu_aio_context in that case since I/O completion callbacks will be
invoked in the main loop thread.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240119135748.270944-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>