[PATCH AUTOSEL 4.19 094/258] nfp: add locking around representor changes

[Sasha Levin]

From: Jakub Kicinski <jakub.kicin...@netronome.com>

[ 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.kicin...@netronome.com>
Reviewed-by: John Hurley <john.hur...@netronome.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 b84a6c2d387b..04ef4b986a43 100644
--- a/drivers/net/ethernet/netronome/nfp/abm/main.c
+++ b/drivers/net/ethernet/netronome/nfp/abm/main.c
@@ -415,7 +415,9 @@ 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",
@@ -441,7 +443,9 @@ 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 8607d09ab732..ba6abe652cce 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.c
@@ -156,7 +156,9 @@ 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 18a09cdcd9c6..6985db8822bd 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
@@ -472,7 +472,9 @@ 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