xdp: Fix xsk_generic_xmit errno

Propagate sock_alloc_send_skb error code, not set it to
EAGAIN unconditionally, when fail to allocate skb, which
might cause that user space unnecessary loops.

Fixes: 35fcde7f8deb ("xsk: support for Tx")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/1591852266-24017-1-git-send-email-lirongqing@baidu.com

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index b6c0f08..3700266 100644 (file)
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -352,10 +352,8 @@ static int xsk_generic_xmit(struct sock *sk)
 
                len = desc.len;
                skb = sock_alloc_send_skb(sk, len, 1, &err);
-               if (unlikely(!skb)) {
-                       err = -EAGAIN;
+               if (unlikely(!skb))
                        goto out;
-               }
 
                skb_put(skb, len);
                addr = desc.addr;