From: Alexander Aring <aring@mojatatu.com>
Date: Wed, 20 Dec 2017 12:35:20 -0500
Subject: net: sch: api: add extack support in qdisc_alloc
Patch-mainline: v4.16-rc1
Git-commit: d0bd684dddab51ed017ece0359f26b038ec31940
References: bsc#1109837

This patch adds extack support for the function qdisc_alloc which is
a common used function in the tc subsystem. Callers which are interested
in the receiving error can assign extack to get a more detailed
information why qdisc_alloc failed.

Cc: David Ahern <dsahern@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/sch_generic.h |    3 ++-
 net/sched/sch_api.c       |    2 +-
 net/sched/sch_generic.c   |    6 ++++--
 3 files changed, 7 insertions(+), 4 deletions(-)

--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -468,7 +468,8 @@ void qdisc_destroy(struct Qdisc *qdisc);
 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 			       unsigned int len);
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
-			  const struct Qdisc_ops *ops);
+			  const struct Qdisc_ops *ops,
+			  struct netlink_ext_ack *extack);
 void qdisc_free(struct Qdisc *qdisc);
 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 				const struct Qdisc_ops *ops, u32 parentid);
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1052,7 +1052,7 @@ static struct Qdisc *qdisc_create(struct
 		goto err_out;
 	}
 
-	sch = qdisc_alloc(dev_queue, ops);
+	sch = qdisc_alloc(dev_queue, ops, extack);
 	if (IS_ERR(sch)) {
 		err = PTR_ERR(sch);
 		goto err_out2;
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -752,7 +752,8 @@ static struct lock_class_key qdisc_tx_bu
 static struct lock_class_key qdisc_running_key;
 
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
-			  const struct Qdisc_ops *ops)
+			  const struct Qdisc_ops *ops,
+			  struct netlink_ext_ack *extack)
 {
 	void *p;
 	struct Qdisc *sch;
@@ -761,6 +762,7 @@ struct Qdisc *qdisc_alloc(struct netdev_
 	struct net_device *dev;
 
 	if (!dev_queue) {
+		NL_SET_ERR_MSG(extack, "No device queue given");
 		err = -EINVAL;
 		goto errout;
 	}
@@ -845,7 +847,7 @@ struct Qdisc *qdisc_create_dflt(struct n
 	if (!try_module_get(ops->owner))
 		return NULL;
 
-	sch = qdisc_alloc(dev_queue, ops);
+	sch = qdisc_alloc(dev_queue, ops, NULL);
 	if (IS_ERR(sch)) {
 		module_put(ops->owner);
 		return NULL;