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@xxxxxxxxxxxxxxxxx>
Reviewed-by: Dust Li <dust.li@xxxxxxxxxxxxxxxxx>
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;
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