From: Li RongQing <lirongqing@baidu.com>
Date: Thu, 11 Jun 2020 13:11:06 +0800
Subject: xdp: Fix xsk_generic_xmit errno
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Patch-mainline: v5.8-rc1
Git-commit: aa2cad0600ed2ca6a0ab39948d4db1666b6c962b
References: bsc#1109837

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
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/xdp/xsk.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -257,10 +257,8 @@ static int xsk_generic_xmit(struct sock
 
 		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;