[PATCH v2] sch_api: Change signature of qdisc_tree_reduce_backlog() to use ints

[PATCH v2] sch_api: Change signature of qdisc_tree_reduce_backlog() to use ints

[Toke Høiland-Jørgensen]

There are now several places where qdisc_tree_reduce_backlog() is called
with a negative number of packets (to signal an increase in number of
packets in the queue). Rather than rely on overflow behaviour, change the
function signature to use signed integers to communicate this usage to
people reading the code.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
 include/net/sch_generic.h | 3 +--
 net/sched/sch_api.c       | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 9481f2c142e2..7a4957599874 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -580,8 +580,7 @@ struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 void qdisc_reset(struct Qdisc *qdisc);
 void qdisc_put(struct Qdisc *qdisc);
 void qdisc_put_unlocked(struct Qdisc *qdisc);
-void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
-			       unsigned int len);
+void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, int n, int len);
 #ifdef CONFIG_NET_SCHED
 int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
 			      void *type_data);
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 7e4d1ccf4c87..03e26e8d0ec9 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -758,8 +758,7 @@ static u32 qdisc_alloc_handle(struct net_device *dev)
 	return 0;
 }
 
-void qdisc_tree_reduce_backlog(struct Qdisc *sch, unsigned int n,
-			       unsigned int len)
+void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
 {
 	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
 	const struct Qdisc_class_ops *cops;
-- 
2.19.1

Re: [PATCH v2] sch_api: Change signature of qdisc_tree_reduce_backlog() to use ints

[David Miller]

From: Toke Høiland-Jørgensen <toke@redhat.com>
Date: Wed,  9 Jan 2019 17:10:57 +0100

> There are now several places where qdisc_tree_reduce_backlog() is called
> with a negative number of packets (to signal an increase in number of
> packets in the queue). Rather than rely on overflow behaviour, change the
> function signature to use signed integers to communicate this usage to
> people reading the code.
> 
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>

Applied to net-next, thanks.