From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Wed, 17 Jan 2018 18:50:58 -0800
Subject: nfp: add nfp_reprs_get_locked() helper
Patch-mainline: v4.16-rc1
Git-commit: e1740fb6c111986a7af96a44ff794b2ba75abb2e
References: bsc#1109837

The write side of repr tables is always done under pf->lock.
Add a helper to dereference repr table pointers under protection
of that 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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/netronome/nfp/nfp_app.c      |   12 ++++++++++--
 drivers/net/ethernet/netronome/nfp/nfp_app.h      |    2 ++
 drivers/net/ethernet/netronome/nfp/nfp_net_repr.c |    4 +---
 3 files changed, 13 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/netronome/nfp/nfp_app.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.c
@@ -32,6 +32,8 @@
  */
 
 #include <linux/bug.h>
+#include <linux/lockdep.h>
+#include <linux/rcupdate.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
 
@@ -99,13 +101,19 @@ nfp_app_ctrl_msg_alloc(struct nfp_app *a
 }
 
 struct nfp_reprs *
+nfp_reprs_get_locked(struct nfp_app *app, enum nfp_repr_type type)
+{
+	return rcu_dereference_protected(app->reprs[type],
+					 lockdep_is_held(&app->pf->lock));
+}
+
+struct nfp_reprs *
 nfp_app_reprs_set(struct nfp_app *app, enum nfp_repr_type type,
 		  struct nfp_reprs *reprs)
 {
 	struct nfp_reprs *old;
 
-	old = rcu_dereference_protected(app->reprs[type],
-					lockdep_is_held(&app->pf->lock));
+	old = nfp_reprs_get_locked(app, type);
 	rcu_assign_pointer(app->reprs[type], reprs);
 
 	return old;
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.h
@@ -385,6 +385,8 @@ static inline struct net_device *nfp_app
 struct nfp_app *nfp_app_from_netdev(struct net_device *netdev);
 
 struct nfp_reprs *
+nfp_reprs_get_locked(struct nfp_app *app, enum nfp_repr_type type);
+struct nfp_reprs *
 nfp_app_reprs_set(struct nfp_app *app, enum nfp_repr_type type,
 		  struct nfp_reprs *reprs);
 
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
@@ -424,9 +424,7 @@ int nfp_reprs_resync_phys_ports(struct n
 	struct nfp_repr *repr;
 	int i;
 
-	old_reprs =
-		rcu_dereference_protected(app->reprs[NFP_REPR_TYPE_PHYS_PORT],
-					  lockdep_is_held(&app->pf->lock));
+	old_reprs = nfp_reprs_get_locked(app, NFP_REPR_TYPE_PHYS_PORT);
 	if (!old_reprs)
 		return 0;