| Message ID | 20210331071139.15473-6-xuanzhuo@linux.alibaba.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio-net support xdp socket zero copy xmit | expand |
在 2021/3/31 下午3:11, Xuan Zhuo 写道: > In xsk unaligned mode, the frame pointed to by desc may span two > consecutive pages, but not more than two pages. > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > Reviewed-by: Dust Li <dust.li@linux.alibaba.com> I'd squash this patch into patch 4. > --- > drivers/net/virtio_net.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index c8a317a93ef7..259fafcf6028 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -2562,24 +2562,42 @@ static void virtnet_xsk_check_space(struct send_queue *sq) > static int virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, > struct xdp_desc *desc) > { > + u32 offset, n, i, copy, copied; Let's use a better name since we don't actually copy anything here. > struct virtnet_info *vi; > struct page *page; > void *data; > - u32 offset; > + int err, m; > u64 addr; > - int err; > > vi = sq->vq->vdev->priv; > addr = desc->addr; > + > data = xsk_buff_raw_get_data(pool, addr); > + > offset = offset_in_page(data); > + m = desc->len - (PAGE_SIZE - offset); > + /* xsk unaligned mode, desc will use two page */ > + if (m > 0) > + n = 3; > + else > + n = 2; > > - sg_init_table(sq->sg, 2); > + sg_init_table(sq->sg, n); > sg_set_buf(sq->sg, &xsk_hdr, vi->hdr_len); > - page = xsk_buff_xdp_get_page(pool, addr); > - sg_set_page(sq->sg + 1, page, desc->len, offset); > > - err = virtqueue_add_outbuf(sq->vq, sq->sg, 2, NULL, GFP_ATOMIC); > + copied = 0; > + for (i = 1; i < n; ++i) { > + copy = min_t(int, desc->len - copied, PAGE_SIZE - offset); > + > + page = xsk_buff_xdp_get_page(pool, addr + copied); > + > + sg_set_page(sq->sg + i, page, copy, offset); > + copied += copy; > + if (offset) > + offset = 0; > + } Can we simplify the codes by using while here? Then I think we don't need to determine the value of n. Thanks > + > + err = virtqueue_add_outbuf(sq->vq, sq->sg, n, NULL, GFP_ATOMIC); > if (unlikely(err)) > sq->xsk.last_desc = *desc; >
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index c8a317a93ef7..259fafcf6028 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2562,24 +2562,42 @@ static void virtnet_xsk_check_space(struct send_queue *sq) static int virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, struct xdp_desc *desc) { + u32 offset, n, i, copy, copied; struct virtnet_info *vi; struct page *page; void *data; - u32 offset; + int err, m; u64 addr; - int err; vi = sq->vq->vdev->priv; addr = desc->addr; + data = xsk_buff_raw_get_data(pool, addr); + offset = offset_in_page(data); + m = desc->len - (PAGE_SIZE - offset); + /* xsk unaligned mode, desc will use two page */ + if (m > 0) + n = 3; + else + n = 2; - sg_init_table(sq->sg, 2); + sg_init_table(sq->sg, n); sg_set_buf(sq->sg, &xsk_hdr, vi->hdr_len); - page = xsk_buff_xdp_get_page(pool, addr); - sg_set_page(sq->sg + 1, page, desc->len, offset); - err = virtqueue_add_outbuf(sq->vq, sq->sg, 2, NULL, GFP_ATOMIC); + copied = 0; + for (i = 1; i < n; ++i) { + copy = min_t(int, desc->len - copied, PAGE_SIZE - offset); + + page = xsk_buff_xdp_get_page(pool, addr + copied); + + sg_set_page(sq->sg + i, page, copy, offset); + copied += copy; + if (offset) + offset = 0; + } + + err = virtqueue_add_outbuf(sq->vq, sq->sg, n, NULL, GFP_ATOMIC); if (unlikely(err)) sq->xsk.last_desc = *desc;