Merge branch 'xfrm & bonding: Correct use of xso.real_dev'

Cosmin Ratiu says:

====================
This patch series was motivated by fixing a few bugs in the bonding
driver related to xfrm state migration on device failover.

struct xfrm_dev_offload has two net_device pointers: dev and real_dev.
The first one is the device the xfrm_state is offloaded on and the
second one is used by the bonding driver to manage the underlying device
xfrm_states are actually offloaded on. When bonding isn't used, the two
pointers are the same.

This causes confusion in drivers: Which device pointer should they use?
If they want to support bonding, they need to only use real_dev and
never look at dev.

Furthermore, real_dev is used without proper locking from multiple code
paths and changing it is dangerous. See commit [1] for example.

This patch series clears things out by removing all uses of real_dev
from outside the bonding driver.
Then, the bonding driver is refactored to fix a couple of long standing
races and the original bug which motivated this patch series.

[1] commit f8cde9805981 ("bonding: fix xfrm real_dev null pointer
dereference")

v2 -> v3:
Added a comment with locking expectations for real_dev.
Removed unnecessary bond variable from bond_ipsec_del_sa().
v1 -> v2:
Added missing kdoc for various functions.
Made bond_ipsec_del_sa() use xso.real_dev instead of curr_active_slave.
====================

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 341d79ecb5c2..3c2e27e5a1e3 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -767,7 +767,7 @@ void xfrm_dev_state_delete(struct xfrm_state *x)
 	struct net_device *dev = READ_ONCE(xso->dev);
 
 	if (dev) {
-		dev->xfrmdev_ops->xdo_dev_state_delete(x);
+		dev->xfrmdev_ops->xdo_dev_state_delete(dev, x);
 		spin_lock_bh(&xfrm_state_dev_gc_lock);
 		hlist_add_head(&x->dev_gclist, &xfrm_state_dev_gc_list);
 		spin_unlock_bh(&xfrm_state_dev_gc_lock);
@@ -789,7 +789,7 @@ void xfrm_dev_state_free(struct xfrm_state *x)
 		spin_unlock_bh(&xfrm_state_dev_gc_lock);
 
 		if (dev->xfrmdev_ops->xdo_dev_state_free)
-			dev->xfrmdev_ops->xdo_dev_state_free(x);
+			dev->xfrmdev_ops->xdo_dev_state_free(dev, x);
 		WRITE_ONCE(xso->dev, NULL);
 		xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
 		netdev_put(dev, &xso->dev_tracker);
@@ -1551,19 +1551,19 @@ found:
 		if (pol->xdo.type == XFRM_DEV_OFFLOAD_PACKET) {
 			struct xfrm_dev_offload *xdo = &pol->xdo;
 			struct xfrm_dev_offload *xso = &x->xso;
+			struct net_device *dev = xdo->dev;
 
 			xso->type = XFRM_DEV_OFFLOAD_PACKET;
 			xso->dir = xdo->dir;
-			xso->dev = xdo->dev;
-			xso->real_dev = xdo->real_dev;
+			xso->dev = dev;
 			xso->flags = XFRM_DEV_OFFLOAD_FLAG_ACQ;
-			netdev_hold(xso->dev, &xso->dev_tracker, GFP_ATOMIC);
-			error = xso->dev->xfrmdev_ops->xdo_dev_state_add(x, NULL);
+			netdev_hold(dev, &xso->dev_tracker, GFP_ATOMIC);
+			error = dev->xfrmdev_ops->xdo_dev_state_add(dev, x,
+								    NULL);
 			if (error) {
 				xso->dir = 0;
-				netdev_put(xso->dev, &xso->dev_tracker);
+				netdev_put(dev, &xso->dev_tracker);
 				xso->dev = NULL;
-				xso->real_dev = NULL;
 				xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
 				x->km.state = XFRM_STATE_DEAD;
 				to_put = x;