nfp: register devlink after app is created

Devlink used to have two global locks: devlink lock and port lock,
our lock ordering looked like this:

  devlink lock -> driver's pf->lock -> devlink port lock

After recent changes port lock was replaced with per-instance
lock.  Unfortunately, new per-instance lock is taken on most
operations now.  This means we can only grab the pf->lock from
the port split/unsplit ops.  Lock ordering looks like this:

  devlink lock -> driver's pf->lock -> devlink instance lock

Since we can't take pf->lock from most devlink ops, make sure
nfp_apps are prepared to service them as soon as devlink is
registered.  Locking the pf must be pushed down after
nfp_app_init() callback.

The init order looks like this:
 nfp_app_init
 devlink_register
 nfp_app_start
 netdev/port_register

As soon as app_init is done nfp_apps must be ready to service
devlink-related callbacks.  apps can only register their own
devlink objects from nfp_app_start.

Fixes: 2406e7e546b2 ("devlink: Add per devlink instance lock")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 11 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
index 6c9f29c2e975..eb0fc614673d 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
@@ -152,18 +152,8 @@ out:
 static int nfp_devlink_eswitch_mode_get(struct devlink *devlink, u16 *mode)
 {
 	struct nfp_pf *pf = devlink_priv(devlink);
-	int ret;
-
-	mutex_lock(&pf->lock);
-	if (!pf->app) {
-		ret = -EBUSY;
-		goto out;
-	}
-	ret = nfp_app_eswitch_mode_get(pf->app, mode);
-out:
-	mutex_unlock(&pf->lock);
 
-	return ret;
+	return nfp_app_eswitch_mode_get(pf->app, mode);
 }
 
 const struct devlink_ops nfp_devlink_ops = {