Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / sched / sch_fifo.c

diff --git a/kernel/net/sched/sch_fifo.c b/kernel/net/sched/sch_fifo.c
new file mode 100644 (file)
index 0000000..2e2398c
--- /dev/null
+++ b/kernel/net/sched/sch_fifo.c
@@ -0,0 +1,180 @@
+/*
+ * net/sched/sch_fifo.c        The simplest FIFO queue.
+ *
+ *             This program is free software; you can redistribute it and/or
+ *             modify it under the terms of the GNU General Public License
+ *             as published by the Free Software Foundation; either version
+ *             2 of the License, or (at your option) any later version.
+ *
+ * Authors:    Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+
+/* 1 band FIFO pseudo-"scheduler" */
+
+static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+       if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit))
+               return qdisc_enqueue_tail(skb, sch);
+
+       return qdisc_reshape_fail(skb, sch);
+}
+
+static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+       if (likely(skb_queue_len(&sch->q) < sch->limit))
+               return qdisc_enqueue_tail(skb, sch);
+
+       return qdisc_reshape_fail(skb, sch);
+}
+
+static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+       if (likely(skb_queue_len(&sch->q) < sch->limit))
+               return qdisc_enqueue_tail(skb, sch);
+
+       /* queue full, remove one skb to fulfill the limit */
+       __qdisc_queue_drop_head(sch, &sch->q);
+       qdisc_qstats_drop(sch);
+       qdisc_enqueue_tail(skb, sch);
+
+       return NET_XMIT_CN;
+}
+
+static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
+{
+       bool bypass;
+       bool is_bfifo = sch->ops == &bfifo_qdisc_ops;
+
+       if (opt == NULL) {
+               u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
+
+               if (is_bfifo)
+                       limit *= psched_mtu(qdisc_dev(sch));
+
+               sch->limit = limit;
+       } else {
+               struct tc_fifo_qopt *ctl = nla_data(opt);
+
+               if (nla_len(opt) < sizeof(*ctl))
+                       return -EINVAL;
+
+               sch->limit = ctl->limit;
+       }
+
+       if (is_bfifo)
+               bypass = sch->limit >= psched_mtu(qdisc_dev(sch));
+       else
+               bypass = sch->limit >= 1;
+
+       if (bypass)
+               sch->flags |= TCQ_F_CAN_BYPASS;
+       else
+               sch->flags &= ~TCQ_F_CAN_BYPASS;
+       return 0;
+}
+
+static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+       struct tc_fifo_qopt opt = { .limit = sch->limit };
+
+       if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
+               goto nla_put_failure;
+       return skb->len;
+
+nla_put_failure:
+       return -1;
+}
+
+struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
+       .id             =       "pfifo",
+       .priv_size      =       0,
+       .enqueue        =       pfifo_enqueue,
+       .dequeue        =       qdisc_dequeue_head,
+       .peek           =       qdisc_peek_head,
+       .drop           =       qdisc_queue_drop,
+       .init           =       fifo_init,
+       .reset          =       qdisc_reset_queue,
+       .change         =       fifo_init,
+       .dump           =       fifo_dump,
+       .owner          =       THIS_MODULE,
+};
+EXPORT_SYMBOL(pfifo_qdisc_ops);
+
+struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
+       .id             =       "bfifo",
+       .priv_size      =       0,
+       .enqueue        =       bfifo_enqueue,
+       .dequeue        =       qdisc_dequeue_head,
+       .peek           =       qdisc_peek_head,
+       .drop           =       qdisc_queue_drop,
+       .init           =       fifo_init,
+       .reset          =       qdisc_reset_queue,
+       .change         =       fifo_init,
+       .dump           =       fifo_dump,
+       .owner          =       THIS_MODULE,
+};
+EXPORT_SYMBOL(bfifo_qdisc_ops);
+
+struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = {
+       .id             =       "pfifo_head_drop",
+       .priv_size      =       0,
+       .enqueue        =       pfifo_tail_enqueue,
+       .dequeue        =       qdisc_dequeue_head,
+       .peek           =       qdisc_peek_head,
+       .drop           =       qdisc_queue_drop_head,
+       .init           =       fifo_init,
+       .reset          =       qdisc_reset_queue,
+       .change         =       fifo_init,
+       .dump           =       fifo_dump,
+       .owner          =       THIS_MODULE,
+};
+
+/* Pass size change message down to embedded FIFO */
+int fifo_set_limit(struct Qdisc *q, unsigned int limit)
+{
+       struct nlattr *nla;
+       int ret = -ENOMEM;
+
+       /* Hack to avoid sending change message to non-FIFO */
+       if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
+               return 0;
+
+       nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
+       if (nla) {
+               nla->nla_type = RTM_NEWQDISC;
+               nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
+               ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
+
+               ret = q->ops->change(q, nla);
+               kfree(nla);
+       }
+       return ret;
+}
+EXPORT_SYMBOL(fifo_set_limit);
+
+struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
+                              unsigned int limit)
+{
+       struct Qdisc *q;
+       int err = -ENOMEM;
+
+       q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1));
+       if (q) {
+               err = fifo_set_limit(q, limit);
+               if (err < 0) {
+                       qdisc_destroy(q);
+                       q = NULL;
+               }
+       }
+
+       return q ? : ERR_PTR(err);
+}
+EXPORT_SYMBOL(fifo_create_dflt);