1/*
2 * Copyright (c) 2016 Qualcomm Atheros, Inc
3 *
4 * GPL v2
5 *
6 * Based on net/sched/sch_fq_codel.c
7 */
8#ifndef __NET_SCHED_FQ_IMPL_H
9#define __NET_SCHED_FQ_IMPL_H
10
11#include <net/fq.h>
12
13/* functions that are embedded into includer */
14
15static void fq_adjust_removal(struct fq *fq,
16 struct fq_flow *flow,
17 struct sk_buff *skb)
18{
19 struct fq_tin *tin = flow->tin;
20
21 tin->backlog_bytes -= skb->len;
22 tin->backlog_packets--;
23 flow->backlog -= skb->len;
24 fq->backlog--;
25 fq->memory_usage -= skb->truesize;
26}
27
28static void fq_rejigger_backlog(struct fq *fq, struct fq_flow *flow)
29{
30 struct fq_flow *i;
31
32 if (flow->backlog == 0) {
33 list_del_init(&flow->backlogchain);
34 } else {
35 i = flow;
36
37 list_for_each_entry_continue(i, &fq->backlogs, backlogchain)
38 if (i->backlog < flow->backlog)
39 break;
40
41 list_move_tail(&flow->backlogchain,
42 &i->backlogchain);
43 }
44}
45
46static struct sk_buff *fq_flow_dequeue(struct fq *fq,
47 struct fq_flow *flow)
48{
49 struct sk_buff *skb;
50
51 lockdep_assert_held(&fq->lock);
52
53 skb = __skb_dequeue(&flow->queue);
54 if (!skb)
55 return NULL;
56
57 fq_adjust_removal(fq, flow, skb);
58 fq_rejigger_backlog(fq, flow);
59
60 return skb;
61}
62
63static struct sk_buff *fq_tin_dequeue(struct fq *fq,
64 struct fq_tin *tin,
65 fq_tin_dequeue_t dequeue_func)
66{
67 struct fq_flow *flow;
68 struct list_head *head;
69 struct sk_buff *skb;
70
71 lockdep_assert_held(&fq->lock);
72
73begin:
74 head = &tin->new_flows;
75 if (list_empty(head)) {
76 head = &tin->old_flows;
77 if (list_empty(head))
78 return NULL;
79 }
80
81 flow = list_first_entry(head, struct fq_flow, flowchain);
82
83 if (flow->deficit <= 0) {
84 flow->deficit += fq->quantum;
85 list_move_tail(&flow->flowchain,
86 &tin->old_flows);
87 goto begin;
88 }
89
90 skb = dequeue_func(fq, tin, flow);
91 if (!skb) {
92 /* force a pass through old_flows to prevent starvation */
93 if ((head == &tin->new_flows) &&
94 !list_empty(&tin->old_flows)) {
95 list_move_tail(&flow->flowchain, &tin->old_flows);
96 } else {
97 list_del_init(&flow->flowchain);
98 flow->tin = NULL;
99 }
100 goto begin;
101 }
102
103 flow->deficit -= skb->len;
104 tin->tx_bytes += skb->len;
105 tin->tx_packets++;
106
107 return skb;
108}
109
110static struct fq_flow *fq_flow_classify(struct fq *fq,
111 struct fq_tin *tin,
112 struct sk_buff *skb,
113 fq_flow_get_default_t get_default_func)
114{
115 struct fq_flow *flow;
116 u32 hash;
117 u32 idx;
118
119 lockdep_assert_held(&fq->lock);
120
121 hash = skb_get_hash_perturb(skb, fq->perturbation);
122 idx = reciprocal_scale(hash, fq->flows_cnt);
123 flow = &fq->flows[idx];
124
125 if (flow->tin && flow->tin != tin) {
126 flow = get_default_func(fq, tin, idx, skb);
127 tin->collisions++;
128 fq->collisions++;
129 }
130
131 if (!flow->tin)
132 tin->flows++;
133
134 return flow;
135}
136
137static void fq_recalc_backlog(struct fq *fq,
138 struct fq_tin *tin,
139 struct fq_flow *flow)
140{
141 struct fq_flow *i;
142
143 if (list_empty(&flow->backlogchain))
144 list_add_tail(&flow->backlogchain, &fq->backlogs);
145
146 i = flow;
147 list_for_each_entry_continue_reverse(i, &fq->backlogs,
148 backlogchain)
149 if (i->backlog > flow->backlog)
150 break;
151
152 list_move(&flow->backlogchain, &i->backlogchain);
153}
154
155static void fq_tin_enqueue(struct fq *fq,
156 struct fq_tin *tin,
157 struct sk_buff *skb,
158 fq_skb_free_t free_func,
159 fq_flow_get_default_t get_default_func)
160{
161 struct fq_flow *flow;
162 bool oom;
163
164 lockdep_assert_held(&fq->lock);
165
166 flow = fq_flow_classify(fq, tin, skb, get_default_func);
167
168 flow->tin = tin;
169 flow->backlog += skb->len;
170 tin->backlog_bytes += skb->len;
171 tin->backlog_packets++;
172 fq->memory_usage += skb->truesize;
173 fq->backlog++;
174
175 fq_recalc_backlog(fq, tin, flow);
176
177 if (list_empty(&flow->flowchain)) {
178 flow->deficit = fq->quantum;
179 list_add_tail(&flow->flowchain,
180 &tin->new_flows);
181 }
182
183 __skb_queue_tail(&flow->queue, skb);
184 oom = (fq->memory_usage > fq->memory_limit);
185 while (fq->backlog > fq->limit || oom) {
186 flow = list_first_entry_or_null(&fq->backlogs,
187 struct fq_flow,
188 backlogchain);
189 if (!flow)
190 return;
191
192 skb = fq_flow_dequeue(fq, flow);
193 if (!skb)
194 return;
195
196 free_func(fq, flow->tin, flow, skb);
197
198 flow->tin->overlimit++;
199 fq->overlimit++;
200 if (oom) {
201 fq->overmemory++;
202 oom = (fq->memory_usage > fq->memory_limit);
203 }
204 }
205}
206
207static void fq_flow_filter(struct fq *fq,
208 struct fq_flow *flow,
209 fq_skb_filter_t filter_func,
210 void *filter_data,
211 fq_skb_free_t free_func)
212{
213 struct fq_tin *tin = flow->tin;
214 struct sk_buff *skb, *tmp;
215
216 lockdep_assert_held(&fq->lock);
217
218 skb_queue_walk_safe(&flow->queue, skb, tmp) {
219 if (!filter_func(fq, tin, flow, skb, filter_data))
220 continue;
221
222 __skb_unlink(skb, &flow->queue);
223 fq_adjust_removal(fq, flow, skb);
224 free_func(fq, tin, flow, skb);
225 }
226
227 fq_rejigger_backlog(fq, flow);
228}
229
230static void fq_tin_filter(struct fq *fq,
231 struct fq_tin *tin,
232 fq_skb_filter_t filter_func,
233 void *filter_data,
234 fq_skb_free_t free_func)
235{
236 struct fq_flow *flow;
237
238 lockdep_assert_held(&fq->lock);
239
240 list_for_each_entry(flow, &tin->new_flows, flowchain)
241 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
242 list_for_each_entry(flow, &tin->old_flows, flowchain)
243 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
244}
245
246static void fq_flow_reset(struct fq *fq,
247 struct fq_flow *flow,
248 fq_skb_free_t free_func)
249{
250 struct sk_buff *skb;
251
252 while ((skb = fq_flow_dequeue(fq, flow)))
253 free_func(fq, flow->tin, flow, skb);
254
255 if (!list_empty(&flow->flowchain))
256 list_del_init(&flow->flowchain);
257
258 if (!list_empty(&flow->backlogchain))
259 list_del_init(&flow->backlogchain);
260
261 flow->tin = NULL;
262
263 WARN_ON_ONCE(flow->backlog);
264}
265
266static void fq_tin_reset(struct fq *fq,
267 struct fq_tin *tin,
268 fq_skb_free_t free_func)
269{
270 struct list_head *head;
271 struct fq_flow *flow;
272
273 for (;;) {
274 head = &tin->new_flows;
275 if (list_empty(head)) {
276 head = &tin->old_flows;
277 if (list_empty(head))
278 break;
279 }
280
281 flow = list_first_entry(head, struct fq_flow, flowchain);
282 fq_flow_reset(fq, flow, free_func);
283 }
284
285 WARN_ON_ONCE(tin->backlog_bytes);
286 WARN_ON_ONCE(tin->backlog_packets);
287}
288
289static void fq_flow_init(struct fq_flow *flow)
290{
291 INIT_LIST_HEAD(&flow->flowchain);
292 INIT_LIST_HEAD(&flow->backlogchain);
293 __skb_queue_head_init(&flow->queue);
294}
295
296static void fq_tin_init(struct fq_tin *tin)
297{
298 INIT_LIST_HEAD(&tin->new_flows);
299 INIT_LIST_HEAD(&tin->old_flows);
300}
301
302static int fq_init(struct fq *fq, int flows_cnt)
303{
304 int i;
305
306 memset(fq, 0, sizeof(fq[0]));
307 INIT_LIST_HEAD(&fq->backlogs);
308 spin_lock_init(&fq->lock);
309 fq->flows_cnt = max_t(u32, flows_cnt, 1);
310 fq->perturbation = prandom_u32();
311 fq->quantum = 300;
312 fq->limit = 8192;
313 fq->memory_limit = 16 << 20; /* 16 MBytes */
314
315 fq->flows = kcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
316 if (!fq->flows)
317 return -ENOMEM;
318
319 for (i = 0; i < fq->flows_cnt; i++)
320 fq_flow_init(&fq->flows[i]);
321
322 return 0;
323}
324
325static void fq_reset(struct fq *fq,
326 fq_skb_free_t free_func)
327{
328 int i;
329
330 for (i = 0; i < fq->flows_cnt; i++)
331 fq_flow_reset(fq, &fq->flows[i], free_func);
332
333 kfree(fq->flows);
334 fq->flows = NULL;
335}
336
337#endif
338