xref: /openbmc/linux/include/net/fq.h (revision 209bccba)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (c) 2016 Qualcomm Atheros, Inc
4  *
5  * Based on net/sched/sch_fq_codel.c
6  */
7 #ifndef __NET_SCHED_FQ_H
8 #define __NET_SCHED_FQ_H
9 
10 #include <linux/skbuff.h>
11 #include <linux/spinlock.h>
12 #include <linux/types.h>
13 
14 struct fq_tin;
15 
16 /**
17  * struct fq_flow - per traffic flow queue
18  *
19  * @tin: owner of this flow. Used to manage collisions, i.e. when a packet
20  *	hashes to an index which points to a flow that is already owned by a
21  *	different tin the packet is destined to. In such case the implementer
22  *	must provide a fallback flow
23  * @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
24  *	(deficit round robin) based round robin queuing similar to the one
25  *	found in net/sched/sch_fq_codel.c
26  * @queue: sk_buff queue to hold packets
27  * @backlog: number of bytes pending in the queue. The number of packets can be
28  *	found in @queue.qlen
29  * @deficit: used for DRR++
30  */
31 struct fq_flow {
32 	struct fq_tin *tin;
33 	struct list_head flowchain;
34 	struct sk_buff_head queue;
35 	u32 backlog;
36 	int deficit;
37 };
38 
39 /**
40  * struct fq_tin - a logical container of fq_flows
41  *
42  * Used to group fq_flows into a logical aggregate. DRR++ scheme is used to
43  * pull interleaved packets out of the associated flows.
44  *
45  * @new_flows: linked list of fq_flow
46  * @old_flows: linked list of fq_flow
47  */
48 struct fq_tin {
49 	struct list_head new_flows;
50 	struct list_head old_flows;
51 	struct list_head tin_list;
52 	struct fq_flow default_flow;
53 	u32 backlog_bytes;
54 	u32 backlog_packets;
55 	u32 overlimit;
56 	u32 collisions;
57 	u32 flows;
58 	u32 tx_bytes;
59 	u32 tx_packets;
60 };
61 
62 /**
63  * struct fq - main container for fair queuing purposes
64  *
65  * @limit: max number of packets that can be queued across all flows
66  * @backlog: number of packets queued across all flows
67  */
68 struct fq {
69 	struct fq_flow *flows;
70 	unsigned long *flows_bitmap;
71 
72 	struct list_head tin_backlog;
73 	spinlock_t lock;
74 	u32 flows_cnt;
75 	u32 limit;
76 	u32 memory_limit;
77 	u32 memory_usage;
78 	u32 quantum;
79 	u32 backlog;
80 	u32 overlimit;
81 	u32 overmemory;
82 	u32 collisions;
83 };
84 
85 typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
86 					 struct fq_tin *,
87 					 struct fq_flow *flow);
88 
89 typedef void fq_skb_free_t(struct fq *,
90 			   struct fq_tin *,
91 			   struct fq_flow *,
92 			   struct sk_buff *);
93 
94 /* Return %true to filter (drop) the frame. */
95 typedef bool fq_skb_filter_t(struct fq *,
96 			     struct fq_tin *,
97 			     struct fq_flow *,
98 			     struct sk_buff *,
99 			     void *);
100 
101 #endif
102