When the cq reservation is failed, the error code is not set which is initialized to zero in __xsk_generic_xmit(). That means the packet is not send successfully but sendto() return ok. Considering the impact on uapi, return -EAGAIN is a good idea. The cq is full usually because it is not released in time, try to send msg again is appropriate. Suggested-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx> Signed-off-by: Wang Liang <wangliang74@xxxxxxxxxx> --- net/xdp/xsk.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 89d2bef96469..e04809a4c5d3 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -802,8 +802,11 @@ static int __xsk_generic_xmit(struct sock *sk) * if there is space in it. This avoids having to implement * any buffering in the Tx path. */ - if (xsk_cq_reserve_addr_locked(xs->pool, desc.addr)) + err = xsk_cq_reserve_addr_locked(xs->pool, desc.addr); + if (err) { + err = -EAGAIN; goto out; + } skb = xsk_build_skb(xs, &desc); if (IS_ERR(skb)) { -- 2.34.1