On Tue, Feb 12, 2013 at 04:32:27PM +0100, Paolo Bonzini wrote: > Il 12/02/2013 15:56, Michael S. Tsirkin ha scritto: > >> > +/** > >> > + * virtqueue_start_buf - start building buffer for the other end > >> > + * @vq: the struct virtqueue we're talking about. > >> > + * @data: the token identifying the buffer. > >> > + * @nents: the number of buffers that will be added > > This function starts building one buffer, number of buffers > > is a bit weird here. > > Ok. > > >> > + * @nsg: the number of sg lists that will be added > > This means number of calls to add_sg ? Not sure why this matters. > > How about we pass in in_num/out_num - that is total # of sg, > > same as add_buf? > > It is used to choose between direct and indirect. total number of in and out should be enough for this, no? > >> > +/** > >> > + * virtqueue_add_sg - add sglist to buffer being built > >> > + * @_vq: the virtqueue for which the buffer is being built > >> > + * @sgl: the description of the buffer(s). > >> > + * @nents: the number of items to process in sgl > >> > + * @dir: whether the sgl is read or written (DMA_TO_DEVICE/DMA_FROM_DEVICE only) > >> > + * > >> > + * Note that, unlike virtqueue_add_buf, this function follows chained > >> > + * scatterlists, and stops before the @nents-th item if a scatterlist item > >> > + * has a marker. > >> > + * > >> > + * Caller must ensure we don't call this with other virtqueue operations > >> > + * at the same time (except where noted). > > Hmm so if you want to add in and out, need separate calls? > > in_num/out_num would be nicer? > > If you want to add in and out just use virtqueue_add_buf... > > Paolo I thought the point of this one is maximum flexibility. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
