[PATCH AUTOSEL 4.19 172/172] xdp: Fix xsk_generic_xmit errno

[Sasha Levin]

From: Li RongQing <lirongqing@xxxxxxxxx>

[ Upstream commit aa2cad0600ed2ca6a0ab39948d4db1666b6c962b ]

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@xxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: BjÃrn TÃpel <bjorn.topel@xxxxxxxxx>
Link: https://lore.kernel.org/bpf/1591852266-24017-1-git-send-email-lirongqing@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/xdp/xsk.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 72caa4fb13f4..9ff2ab63e639 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -233,10 +233,8 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
 
 		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;
-- 
2.25.1