[PATCH AUTOSEL 4.20 109/304] nfp: add locking around representor changes

[Sasha Levin]

From: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>

[ Upstream commit 71844fac1ed459024dd2a448d63d5b28b8c87daa ]

Up until now we never needed to keep a networking locks around
representors accesses, we only accessed them when device was
reconfigured (under nfp pf->lock) or on fast path (under RCU).
Now we want to be able to iterate over all representors during
notifications, so make sure representor assignment is done
under RTNL lock.

Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
Reviewed-by: John Hurley <john.hurley@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/netronome/nfp/abm/main.c     | 4 ++++
 drivers/net/ethernet/netronome/nfp/nfp_app.c      | 2 ++
 drivers/net/ethernet/netronome/nfp/nfp_net_repr.c | 2 ++
 3 files changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/abm/main.c b/drivers/net/ethernet/netronome/nfp/abm/main.c
index c0830c0c2c3f..376df412ea55 100644
--- a/drivers/net/ethernet/netronome/nfp/abm/main.c
+++ b/drivers/net/ethernet/netronome/nfp/abm/main.c
@@ -384,7 +384,9 @@ nfp_abm_spawn_repr(struct nfp_app *app, struct nfp_abm_link *alink,
 
 	reprs = nfp_reprs_get_locked(app, rtype);
 	WARN(nfp_repr_get_locked(app, reprs, alink->id), "duplicate repr");
+	rtnl_lock();
 	rcu_assign_pointer(reprs->reprs[alink->id], netdev);
+	rtnl_unlock();
 
 	nfp_info(app->cpp, "%s Port %d Representor(%s) created\n",
 		 ptype == NFP_PORT_PF_PORT ? "PCIe" : "Phys",
@@ -410,7 +412,9 @@ nfp_abm_kill_repr(struct nfp_app *app, struct nfp_abm_link *alink,
 	netdev = nfp_repr_get_locked(app, reprs, alink->id);
 	if (!netdev)
 		return;
+	rtnl_lock();
 	rcu_assign_pointer(reprs->reprs[alink->id], NULL);
+	rtnl_unlock();
 	synchronize_rcu();
 	/* Cast to make sure nfp_repr_clean_and_free() takes a nfp_repr */
 	nfp_repr_clean_and_free((struct nfp_repr *)netdev_priv(netdev));
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.c b/drivers/net/ethernet/netronome/nfp/nfp_app.c
index 68a0991aac22..3bd1386162b9 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.c
@@ -131,7 +131,9 @@ nfp_app_reprs_set(struct nfp_app *app, enum nfp_repr_type type,
 	struct nfp_reprs *old;
 
 	old = nfp_reprs_get_locked(app, type);
+	rtnl_lock();
 	rcu_assign_pointer(app->reprs[type], reprs);
+	rtnl_unlock();
 
 	return old;
 }
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
index c09b893c30dd..0cf3f40eb8cf 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
@@ -442,7 +442,9 @@ int nfp_reprs_resync_phys_ports(struct nfp_app *app)
 			continue;
 
 		nfp_app_repr_preclean(app, netdev);
+		rtnl_lock();
 		rcu_assign_pointer(reprs->reprs[i], NULL);
+		rtnl_unlock();
 		synchronize_rcu();
 		nfp_repr_clean(repr);
 	}
-- 
2.19.1