From: Ayush Sawal <ayush.sawal@chelsio.com>
Date: Tue, 22 Jun 2021 09:25:31 +0530
Subject: xfrm: Fix xfrm offload fallback fail case
Patch-mainline: v5.14-rc1
Git-commit: dd72fadf2186fc8a6018f97fe72f4d5ca05df440
References: bsc#1176447

In case of xfrm offload, if xdo_dev_state_add() of driver returns
-EOPNOTSUPP, xfrm offload fallback is failed.
In xfrm state_add() both xso->dev and xso->real_dev are initialized to
dev and when err(-EOPNOTSUPP) is returned only xso->dev is set to null.

So in this scenario the condition in func validate_xmit_xfrm(),
if ((x->xso.dev != dev) && (x->xso.real_dev == dev))
                return skb;
returns true, due to which skb is returned without calling esp_xmit()
below which has fallback code. Hence the CRYPTO_FALLBACK is failing.

So fixing this with by keeping x->xso.real_dev as NULL when err is
returned in func xfrm_dev_state_add().

Fixes: bdfd2d1fa79a ("bonding/xfrm: use real_dev instead of slave_dev")
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/xfrm/xfrm_device.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -268,6 +268,7 @@ int xfrm_dev_state_add(struct net *net,
 		xso->num_exthdrs = 0;
 		xso->flags = 0;
 		xso->dev = NULL;
+		xso->real_dev = NULL;
 		dev_put(dev);
 
 		if (err != -EOPNOTSUPP)