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. >> > +/** >> > + * 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
