On Wed, 29 Mar 2017 23:48:53 +0300 "Michael S. Tsirkin" <[email protected]> wrote:
> Allow extra context per descriptor. To avoid slow down for data path, > this disables use of indirect descriptors for this vq. > > Signed-off-by: Michael S. Tsirkin <[email protected]> > --- > drivers/virtio/virtio_ring.c | 70 > ++++++++++++++++++++++++++++++++++++-------- > include/linux/virtio.h | 9 ++++++ > 2 files changed, 66 insertions(+), 13 deletions(-) > > /** > + * virtqueue_add_inbuf_ctx - expose input buffers to other end > + * @vq: the struct virtqueue we're talking about. > + * @sg: scatterlist (must be well-formed and terminated!) > + * @num: the number of entries in @sg writable by other side > + * @data: the token identifying the buffer. > + * @ctx: extra context for the token I think that needs do that ctx != NULL collides with indirect descriptors. > + * @gfp: how to do memory allocations (if necessary). > + * > + * Caller must ensure we don't call this with other virtqueue operations > + * at the same time (except where noted). > + * > + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). > + */ > +int virtqueue_add_inbuf_ctx(struct virtqueue *vq, > + struct scatterlist *sg, unsigned int num, > + void *data, > + void *ctx, > + gfp_t gfp) > +{ > + return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp); > +} > +EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
