On Fri, Dec 29, 2023 at 3:31 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote: > > introduce virtqueue_get_buf_ctx_dma() to collect the dma info when > get buf from virtio core for premapped mode. > > If the virtio queue is premapped mode, the virtio-net send buf may > have many desc. Every desc dma address need to be unmap. So here we > introduce a new helper to collect the dma address of the buffer from > the virtio core. > > Because the BAD_RING is called (that may set vq->broken), so > the relative "const" of vq is removed. > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> > --- > drivers/virtio/virtio_ring.c | 174 +++++++++++++++++++++++++---------- > include/linux/virtio.h | 16 ++++ > 2 files changed, 142 insertions(+), 48 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 51d8f3299c10..1374b3fd447c 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -362,6 +362,45 @@ static struct device *vring_dma_dev(const struct vring_virtqueue *vq) > return vq->dma_dev; > } > > +/* > + * use_dma_api premapped -> do_unmap > + * 1. false false false > + * 2. true false true > + * 3. true true false > + * > + * Only #3, we should return the DMA info to the driver. Btw, I guess you meant "#3 is false" here? And could we reduce the size of these 3 * 3 matrices? It's usually a hint that the code is not optmized. Thanks
