xref: /openbmc/linux/net/sched/sch_hfsc.c (revision fe4549b1)
1 /*
2  * Copyright (c) 2003 Patrick McHardy, <kaber@trash.net>
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (at your option) any later version.
8  *
9  * 2003-10-17 - Ported from altq
10  */
11 /*
12  * Copyright (c) 1997-1999 Carnegie Mellon University. All Rights Reserved.
13  *
14  * Permission to use, copy, modify, and distribute this software and
15  * its documentation is hereby granted (including for commercial or
16  * for-profit use), provided that both the copyright notice and this
17  * permission notice appear in all copies of the software, derivative
18  * works, or modified versions, and any portions thereof.
19  *
20  * THIS SOFTWARE IS EXPERIMENTAL AND IS KNOWN TO HAVE BUGS, SOME OF
21  * WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON PROVIDES THIS
22  * SOFTWARE IN ITS ``AS IS'' CONDITION, AND ANY EXPRESS OR IMPLIED
23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25  * DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
28  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
29  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
30  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
32  * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
33  * DAMAGE.
34  *
35  * Carnegie Mellon encourages (but does not require) users of this
36  * software to return any improvements or extensions that they make,
37  * and to grant Carnegie Mellon the rights to redistribute these
38  * changes without encumbrance.
39  */
40 /*
41  * H-FSC is described in Proceedings of SIGCOMM'97,
42  * "A Hierarchical Fair Service Curve Algorithm for Link-Sharing,
43  * Real-Time and Priority Service"
44  * by Ion Stoica, Hui Zhang, and T. S. Eugene Ng.
45  *
46  * Oleg Cherevko <olwi@aq.ml.com.ua> added the upperlimit for link-sharing.
47  * when a class has an upperlimit, the fit-time is computed from the
48  * upperlimit service curve.  the link-sharing scheduler does not schedule
49  * a class whose fit-time exceeds the current time.
50  */
51 
52 #include <linux/kernel.h>
53 #include <linux/module.h>
54 #include <linux/types.h>
55 #include <linux/errno.h>
56 #include <linux/compiler.h>
57 #include <linux/spinlock.h>
58 #include <linux/skbuff.h>
59 #include <linux/string.h>
60 #include <linux/slab.h>
61 #include <linux/list.h>
62 #include <linux/rbtree.h>
63 #include <linux/init.h>
64 #include <linux/rtnetlink.h>
65 #include <linux/pkt_sched.h>
66 #include <net/netlink.h>
67 #include <net/pkt_sched.h>
68 #include <net/pkt_cls.h>
69 #include <asm/div64.h>
70 
71 /*
72  * kernel internal service curve representation:
73  *   coordinates are given by 64 bit unsigned integers.
74  *   x-axis: unit is clock count.
75  *   y-axis: unit is byte.
76  *
77  *   The service curve parameters are converted to the internal
78  *   representation. The slope values are scaled to avoid overflow.
79  *   the inverse slope values as well as the y-projection of the 1st
80  *   segment are kept in order to avoid 64-bit divide operations
81  *   that are expensive on 32-bit architectures.
82  */
83 
84 struct internal_sc {
85 	u64	sm1;	/* scaled slope of the 1st segment */
86 	u64	ism1;	/* scaled inverse-slope of the 1st segment */
87 	u64	dx;	/* the x-projection of the 1st segment */
88 	u64	dy;	/* the y-projection of the 1st segment */
89 	u64	sm2;	/* scaled slope of the 2nd segment */
90 	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
91 };
92 
93 /* runtime service curve */
94 struct runtime_sc {
95 	u64	x;	/* current starting position on x-axis */
96 	u64	y;	/* current starting position on y-axis */
97 	u64	sm1;	/* scaled slope of the 1st segment */
98 	u64	ism1;	/* scaled inverse-slope of the 1st segment */
99 	u64	dx;	/* the x-projection of the 1st segment */
100 	u64	dy;	/* the y-projection of the 1st segment */
101 	u64	sm2;	/* scaled slope of the 2nd segment */
102 	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
103 };
104 
105 enum hfsc_class_flags {
106 	HFSC_RSC = 0x1,
107 	HFSC_FSC = 0x2,
108 	HFSC_USC = 0x4
109 };
110 
111 struct hfsc_class {
112 	struct Qdisc_class_common cl_common;
113 
114 	struct gnet_stats_basic_sync bstats;
115 	struct gnet_stats_queue qstats;
116 	struct net_rate_estimator __rcu *rate_est;
117 	struct tcf_proto __rcu *filter_list; /* filter list */
118 	struct tcf_block *block;
119 	unsigned int	level;		/* class level in hierarchy */
120 
121 	struct hfsc_sched *sched;	/* scheduler data */
122 	struct hfsc_class *cl_parent;	/* parent class */
123 	struct list_head siblings;	/* sibling classes */
124 	struct list_head children;	/* child classes */
125 	struct Qdisc	*qdisc;		/* leaf qdisc */
126 
127 	struct rb_node el_node;		/* qdisc's eligible tree member */
128 	struct rb_root vt_tree;		/* active children sorted by cl_vt */
129 	struct rb_node vt_node;		/* parent's vt_tree member */
130 	struct rb_root cf_tree;		/* active children sorted by cl_f */
131 	struct rb_node cf_node;		/* parent's cf_heap member */
132 
133 	u64	cl_total;		/* total work in bytes */
134 	u64	cl_cumul;		/* cumulative work in bytes done by
135 					   real-time criteria */
136 
137 	u64	cl_d;			/* deadline*/
138 	u64	cl_e;			/* eligible time */
139 	u64	cl_vt;			/* virtual time */
140 	u64	cl_f;			/* time when this class will fit for
141 					   link-sharing, max(myf, cfmin) */
142 	u64	cl_myf;			/* my fit-time (calculated from this
143 					   class's own upperlimit curve) */
144 	u64	cl_cfmin;		/* earliest children's fit-time (used
145 					   with cl_myf to obtain cl_f) */
146 	u64	cl_cvtmin;		/* minimal virtual time among the
147 					   children fit for link-sharing
148 					   (monotonic within a period) */
149 	u64	cl_vtadj;		/* intra-period cumulative vt
150 					   adjustment */
151 	u64	cl_cvtoff;		/* largest virtual time seen among
152 					   the children */
153 
154 	struct internal_sc cl_rsc;	/* internal real-time service curve */
155 	struct internal_sc cl_fsc;	/* internal fair service curve */
156 	struct internal_sc cl_usc;	/* internal upperlimit service curve */
157 	struct runtime_sc cl_deadline;	/* deadline curve */
158 	struct runtime_sc cl_eligible;	/* eligible curve */
159 	struct runtime_sc cl_virtual;	/* virtual curve */
160 	struct runtime_sc cl_ulimit;	/* upperlimit curve */
161 
162 	u8		cl_flags;	/* which curves are valid */
163 	u32		cl_vtperiod;	/* vt period sequence number */
164 	u32		cl_parentperiod;/* parent's vt period sequence number*/
165 	u32		cl_nactive;	/* number of active children */
166 };
167 
168 struct hfsc_sched {
169 	u16	defcls;				/* default class id */
170 	struct hfsc_class root;			/* root class */
171 	struct Qdisc_class_hash clhash;		/* class hash */
172 	struct rb_root eligible;		/* eligible tree */
173 	struct qdisc_watchdog watchdog;		/* watchdog timer */
174 };
175 
176 #define	HT_INFINITY	0xffffffffffffffffULL	/* infinite time value */
177 
178 
179 /*
180  * eligible tree holds backlogged classes being sorted by their eligible times.
181  * there is one eligible tree per hfsc instance.
182  */
183 
184 static void
185 eltree_insert(struct hfsc_class *cl)
186 {
187 	struct rb_node **p = &cl->sched->eligible.rb_node;
188 	struct rb_node *parent = NULL;
189 	struct hfsc_class *cl1;
190 
191 	while (*p != NULL) {
192 		parent = *p;
193 		cl1 = rb_entry(parent, struct hfsc_class, el_node);
194 		if (cl->cl_e >= cl1->cl_e)
195 			p = &parent->rb_right;
196 		else
197 			p = &parent->rb_left;
198 	}
199 	rb_link_node(&cl->el_node, parent, p);
200 	rb_insert_color(&cl->el_node, &cl->sched->eligible);
201 }
202 
203 static inline void
204 eltree_remove(struct hfsc_class *cl)
205 {
206 	rb_erase(&cl->el_node, &cl->sched->eligible);
207 }
208 
209 static inline void
210 eltree_update(struct hfsc_class *cl)
211 {
212 	eltree_remove(cl);
213 	eltree_insert(cl);
214 }
215 
216 /* find the class with the minimum deadline among the eligible classes */
217 static inline struct hfsc_class *
218 eltree_get_mindl(struct hfsc_sched *q, u64 cur_time)
219 {
220 	struct hfsc_class *p, *cl = NULL;
221 	struct rb_node *n;
222 
223 	for (n = rb_first(&q->eligible); n != NULL; n = rb_next(n)) {
224 		p = rb_entry(n, struct hfsc_class, el_node);
225 		if (p->cl_e > cur_time)
226 			break;
227 		if (cl == NULL || p->cl_d < cl->cl_d)
228 			cl = p;
229 	}
230 	return cl;
231 }
232 
233 /* find the class with minimum eligible time among the eligible classes */
234 static inline struct hfsc_class *
235 eltree_get_minel(struct hfsc_sched *q)
236 {
237 	struct rb_node *n;
238 
239 	n = rb_first(&q->eligible);
240 	if (n == NULL)
241 		return NULL;
242 	return rb_entry(n, struct hfsc_class, el_node);
243 }
244 
245 /*
246  * vttree holds holds backlogged child classes being sorted by their virtual
247  * time. each intermediate class has one vttree.
248  */
249 static void
250 vttree_insert(struct hfsc_class *cl)
251 {
252 	struct rb_node **p = &cl->cl_parent->vt_tree.rb_node;
253 	struct rb_node *parent = NULL;
254 	struct hfsc_class *cl1;
255 
256 	while (*p != NULL) {
257 		parent = *p;
258 		cl1 = rb_entry(parent, struct hfsc_class, vt_node);
259 		if (cl->cl_vt >= cl1->cl_vt)
260 			p = &parent->rb_right;
261 		else
262 			p = &parent->rb_left;
263 	}
264 	rb_link_node(&cl->vt_node, parent, p);
265 	rb_insert_color(&cl->vt_node, &cl->cl_parent->vt_tree);
266 }
267 
268 static inline void
269 vttree_remove(struct hfsc_class *cl)
270 {
271 	rb_erase(&cl->vt_node, &cl->cl_parent->vt_tree);
272 }
273 
274 static inline void
275 vttree_update(struct hfsc_class *cl)
276 {
277 	vttree_remove(cl);
278 	vttree_insert(cl);
279 }
280 
281 static inline struct hfsc_class *
282 vttree_firstfit(struct hfsc_class *cl, u64 cur_time)
283 {
284 	struct hfsc_class *p;
285 	struct rb_node *n;
286 
287 	for (n = rb_first(&cl->vt_tree); n != NULL; n = rb_next(n)) {
288 		p = rb_entry(n, struct hfsc_class, vt_node);
289 		if (p->cl_f <= cur_time)
290 			return p;
291 	}
292 	return NULL;
293 }
294 
295 /*
296  * get the leaf class with the minimum vt in the hierarchy
297  */
298 static struct hfsc_class *
299 vttree_get_minvt(struct hfsc_class *cl, u64 cur_time)
300 {
301 	/* if root-class's cfmin is bigger than cur_time nothing to do */
302 	if (cl->cl_cfmin > cur_time)
303 		return NULL;
304 
305 	while (cl->level > 0) {
306 		cl = vttree_firstfit(cl, cur_time);
307 		if (cl == NULL)
308 			return NULL;
309 		/*
310 		 * update parent's cl_cvtmin.
311 		 */
312 		if (cl->cl_parent->cl_cvtmin < cl->cl_vt)
313 			cl->cl_parent->cl_cvtmin = cl->cl_vt;
314 	}
315 	return cl;
316 }
317 
318 static void
319 cftree_insert(struct hfsc_class *cl)
320 {
321 	struct rb_node **p = &cl->cl_parent->cf_tree.rb_node;
322 	struct rb_node *parent = NULL;
323 	struct hfsc_class *cl1;
324 
325 	while (*p != NULL) {
326 		parent = *p;
327 		cl1 = rb_entry(parent, struct hfsc_class, cf_node);
328 		if (cl->cl_f >= cl1->cl_f)
329 			p = &parent->rb_right;
330 		else
331 			p = &parent->rb_left;
332 	}
333 	rb_link_node(&cl->cf_node, parent, p);
334 	rb_insert_color(&cl->cf_node, &cl->cl_parent->cf_tree);
335 }
336 
337 static inline void
338 cftree_remove(struct hfsc_class *cl)
339 {
340 	rb_erase(&cl->cf_node, &cl->cl_parent->cf_tree);
341 }
342 
343 static inline void
344 cftree_update(struct hfsc_class *cl)
345 {
346 	cftree_remove(cl);
347 	cftree_insert(cl);
348 }
349 
350 /*
351  * service curve support functions
352  *
353  *  external service curve parameters
354  *	m: bps
355  *	d: us
356  *  internal service curve parameters
357  *	sm: (bytes/psched_us) << SM_SHIFT
358  *	ism: (psched_us/byte) << ISM_SHIFT
359  *	dx: psched_us
360  *
361  * The clock source resolution with ktime and PSCHED_SHIFT 10 is 1.024us.
362  *
363  * sm and ism are scaled in order to keep effective digits.
364  * SM_SHIFT and ISM_SHIFT are selected to keep at least 4 effective
365  * digits in decimal using the following table.
366  *
367  *  bits/sec      100Kbps     1Mbps     10Mbps     100Mbps    1Gbps
368  *  ------------+-------------------------------------------------------
369  *  bytes/1.024us 12.8e-3    128e-3     1280e-3    12800e-3   128000e-3
370  *
371  *  1.024us/byte  78.125     7.8125     0.78125    0.078125   0.0078125
372  *
373  * So, for PSCHED_SHIFT 10 we need: SM_SHIFT 20, ISM_SHIFT 18.
374  */
375 #define	SM_SHIFT	(30 - PSCHED_SHIFT)
376 #define	ISM_SHIFT	(8 + PSCHED_SHIFT)
377 
378 #define	SM_MASK		((1ULL << SM_SHIFT) - 1)
379 #define	ISM_MASK	((1ULL << ISM_SHIFT) - 1)
380 
381 static inline u64
382 seg_x2y(u64 x, u64 sm)
383 {
384 	u64 y;
385 
386 	/*
387 	 * compute
388 	 *	y = x * sm >> SM_SHIFT
389 	 * but divide it for the upper and lower bits to avoid overflow
390 	 */
391 	y = (x >> SM_SHIFT) * sm + (((x & SM_MASK) * sm) >> SM_SHIFT);
392 	return y;
393 }
394 
395 static inline u64
396 seg_y2x(u64 y, u64 ism)
397 {
398 	u64 x;
399 
400 	if (y == 0)
401 		x = 0;
402 	else if (ism == HT_INFINITY)
403 		x = HT_INFINITY;
404 	else {
405 		x = (y >> ISM_SHIFT) * ism
406 		    + (((y & ISM_MASK) * ism) >> ISM_SHIFT);
407 	}
408 	return x;
409 }
410 
411 /* Convert m (bps) into sm (bytes/psched us) */
412 static u64
413 m2sm(u32 m)
414 {
415 	u64 sm;
416 
417 	sm = ((u64)m << SM_SHIFT);
418 	sm += PSCHED_TICKS_PER_SEC - 1;
419 	do_div(sm, PSCHED_TICKS_PER_SEC);
420 	return sm;
421 }
422 
423 /* convert m (bps) into ism (psched us/byte) */
424 static u64
425 m2ism(u32 m)
426 {
427 	u64 ism;
428 
429 	if (m == 0)
430 		ism = HT_INFINITY;
431 	else {
432 		ism = ((u64)PSCHED_TICKS_PER_SEC << ISM_SHIFT);
433 		ism += m - 1;
434 		do_div(ism, m);
435 	}
436 	return ism;
437 }
438 
439 /* convert d (us) into dx (psched us) */
440 static u64
441 d2dx(u32 d)
442 {
443 	u64 dx;
444 
445 	dx = ((u64)d * PSCHED_TICKS_PER_SEC);
446 	dx += USEC_PER_SEC - 1;
447 	do_div(dx, USEC_PER_SEC);
448 	return dx;
449 }
450 
451 /* convert sm (bytes/psched us) into m (bps) */
452 static u32
453 sm2m(u64 sm)
454 {
455 	u64 m;
456 
457 	m = (sm * PSCHED_TICKS_PER_SEC) >> SM_SHIFT;
458 	return (u32)m;
459 }
460 
461 /* convert dx (psched us) into d (us) */
462 static u32
463 dx2d(u64 dx)
464 {
465 	u64 d;
466 
467 	d = dx * USEC_PER_SEC;
468 	do_div(d, PSCHED_TICKS_PER_SEC);
469 	return (u32)d;
470 }
471 
472 static void
473 sc2isc(struct tc_service_curve *sc, struct internal_sc *isc)
474 {
475 	isc->sm1  = m2sm(sc->m1);
476 	isc->ism1 = m2ism(sc->m1);
477 	isc->dx   = d2dx(sc->d);
478 	isc->dy   = seg_x2y(isc->dx, isc->sm1);
479 	isc->sm2  = m2sm(sc->m2);
480 	isc->ism2 = m2ism(sc->m2);
481 }
482 
483 /*
484  * initialize the runtime service curve with the given internal
485  * service curve starting at (x, y).
486  */
487 static void
488 rtsc_init(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
489 {
490 	rtsc->x	   = x;
491 	rtsc->y    = y;
492 	rtsc->sm1  = isc->sm1;
493 	rtsc->ism1 = isc->ism1;
494 	rtsc->dx   = isc->dx;
495 	rtsc->dy   = isc->dy;
496 	rtsc->sm2  = isc->sm2;
497 	rtsc->ism2 = isc->ism2;
498 }
499 
500 /*
501  * calculate the y-projection of the runtime service curve by the
502  * given x-projection value
503  */
504 static u64
505 rtsc_y2x(struct runtime_sc *rtsc, u64 y)
506 {
507 	u64 x;
508 
509 	if (y < rtsc->y)
510 		x = rtsc->x;
511 	else if (y <= rtsc->y + rtsc->dy) {
512 		/* x belongs to the 1st segment */
513 		if (rtsc->dy == 0)
514 			x = rtsc->x + rtsc->dx;
515 		else
516 			x = rtsc->x + seg_y2x(y - rtsc->y, rtsc->ism1);
517 	} else {
518 		/* x belongs to the 2nd segment */
519 		x = rtsc->x + rtsc->dx
520 		    + seg_y2x(y - rtsc->y - rtsc->dy, rtsc->ism2);
521 	}
522 	return x;
523 }
524 
525 static u64
526 rtsc_x2y(struct runtime_sc *rtsc, u64 x)
527 {
528 	u64 y;
529 
530 	if (x <= rtsc->x)
531 		y = rtsc->y;
532 	else if (x <= rtsc->x + rtsc->dx)
533 		/* y belongs to the 1st segment */
534 		y = rtsc->y + seg_x2y(x - rtsc->x, rtsc->sm1);
535 	else
536 		/* y belongs to the 2nd segment */
537 		y = rtsc->y + rtsc->dy
538 		    + seg_x2y(x - rtsc->x - rtsc->dx, rtsc->sm2);
539 	return y;
540 }
541 
542 /*
543  * update the runtime service curve by taking the minimum of the current
544  * runtime service curve and the service curve starting at (x, y).
545  */
546 static void
547 rtsc_min(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
548 {
549 	u64 y1, y2, dx, dy;
550 	u32 dsm;
551 
552 	if (isc->sm1 <= isc->sm2) {
553 		/* service curve is convex */
554 		y1 = rtsc_x2y(rtsc, x);
555 		if (y1 < y)
556 			/* the current rtsc is smaller */
557 			return;
558 		rtsc->x = x;
559 		rtsc->y = y;
560 		return;
561 	}
562 
563 	/*
564 	 * service curve is concave
565 	 * compute the two y values of the current rtsc
566 	 *	y1: at x
567 	 *	y2: at (x + dx)
568 	 */
569 	y1 = rtsc_x2y(rtsc, x);
570 	if (y1 <= y) {
571 		/* rtsc is below isc, no change to rtsc */
572 		return;
573 	}
574 
575 	y2 = rtsc_x2y(rtsc, x + isc->dx);
576 	if (y2 >= y + isc->dy) {
577 		/* rtsc is above isc, replace rtsc by isc */
578 		rtsc->x = x;
579 		rtsc->y = y;
580 		rtsc->dx = isc->dx;
581 		rtsc->dy = isc->dy;
582 		return;
583 	}
584 
585 	/*
586 	 * the two curves intersect
587 	 * compute the offsets (dx, dy) using the reverse
588 	 * function of seg_x2y()
589 	 *	seg_x2y(dx, sm1) == seg_x2y(dx, sm2) + (y1 - y)
590 	 */
591 	dx = (y1 - y) << SM_SHIFT;
592 	dsm = isc->sm1 - isc->sm2;
593 	do_div(dx, dsm);
594 	/*
595 	 * check if (x, y1) belongs to the 1st segment of rtsc.
596 	 * if so, add the offset.
597 	 */
598 	if (rtsc->x + rtsc->dx > x)
599 		dx += rtsc->x + rtsc->dx - x;
600 	dy = seg_x2y(dx, isc->sm1);
601 
602 	rtsc->x = x;
603 	rtsc->y = y;
604 	rtsc->dx = dx;
605 	rtsc->dy = dy;
606 }
607 
608 static void
609 init_ed(struct hfsc_class *cl, unsigned int next_len)
610 {
611 	u64 cur_time = psched_get_time();
612 
613 	/* update the deadline curve */
614 	rtsc_min(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);
615 
616 	/*
617 	 * update the eligible curve.
618 	 * for concave, it is equal to the deadline curve.
619 	 * for convex, it is a linear curve with slope m2.
620 	 */
621 	cl->cl_eligible = cl->cl_deadline;
622 	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
623 		cl->cl_eligible.dx = 0;
624 		cl->cl_eligible.dy = 0;
625 	}
626 
627 	/* compute e and d */
628 	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
629 	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
630 
631 	eltree_insert(cl);
632 }
633 
634 static void
635 update_ed(struct hfsc_class *cl, unsigned int next_len)
636 {
637 	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
638 	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
639 
640 	eltree_update(cl);
641 }
642 
643 static inline void
644 update_d(struct hfsc_class *cl, unsigned int next_len)
645 {
646 	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
647 }
648 
649 static inline void
650 update_cfmin(struct hfsc_class *cl)
651 {
652 	struct rb_node *n = rb_first(&cl->cf_tree);
653 	struct hfsc_class *p;
654 
655 	if (n == NULL) {
656 		cl->cl_cfmin = 0;
657 		return;
658 	}
659 	p = rb_entry(n, struct hfsc_class, cf_node);
660 	cl->cl_cfmin = p->cl_f;
661 }
662 
663 static void
664 init_vf(struct hfsc_class *cl, unsigned int len)
665 {
666 	struct hfsc_class *max_cl;
667 	struct rb_node *n;
668 	u64 vt, f, cur_time;
669 	int go_active;
670 
671 	cur_time = 0;
672 	go_active = 1;
673 	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
674 		if (go_active && cl->cl_nactive++ == 0)
675 			go_active = 1;
676 		else
677 			go_active = 0;
678 
679 		if (go_active) {
680 			n = rb_last(&cl->cl_parent->vt_tree);
681 			if (n != NULL) {
682 				max_cl = rb_entry(n, struct hfsc_class, vt_node);
683 				/*
684 				 * set vt to the average of the min and max
685 				 * classes.  if the parent's period didn't
686 				 * change, don't decrease vt of the class.
687 				 */
688 				vt = max_cl->cl_vt;
689 				if (cl->cl_parent->cl_cvtmin != 0)
690 					vt = (cl->cl_parent->cl_cvtmin + vt)/2;
691 
692 				if (cl->cl_parent->cl_vtperiod !=
693 				    cl->cl_parentperiod || vt > cl->cl_vt)
694 					cl->cl_vt = vt;
695 			} else {
696 				/*
697 				 * first child for a new parent backlog period.
698 				 * initialize cl_vt to the highest value seen
699 				 * among the siblings. this is analogous to
700 				 * what cur_time would provide in realtime case.
701 				 */
702 				cl->cl_vt = cl->cl_parent->cl_cvtoff;
703 				cl->cl_parent->cl_cvtmin = 0;
704 			}
705 
706 			/* update the virtual curve */
707 			rtsc_min(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
708 			cl->cl_vtadj = 0;
709 
710 			cl->cl_vtperiod++;  /* increment vt period */
711 			cl->cl_parentperiod = cl->cl_parent->cl_vtperiod;
712 			if (cl->cl_parent->cl_nactive == 0)
713 				cl->cl_parentperiod++;
714 			cl->cl_f = 0;
715 
716 			vttree_insert(cl);
717 			cftree_insert(cl);
718 
719 			if (cl->cl_flags & HFSC_USC) {
720 				/* class has upper limit curve */
721 				if (cur_time == 0)
722 					cur_time = psched_get_time();
723 
724 				/* update the ulimit curve */
725 				rtsc_min(&cl->cl_ulimit, &cl->cl_usc, cur_time,
726 					 cl->cl_total);
727 				/* compute myf */
728 				cl->cl_myf = rtsc_y2x(&cl->cl_ulimit,
729 						      cl->cl_total);
730 			}
731 		}
732 
733 		f = max(cl->cl_myf, cl->cl_cfmin);
734 		if (f != cl->cl_f) {
735 			cl->cl_f = f;
736 			cftree_update(cl);
737 		}
738 		update_cfmin(cl->cl_parent);
739 	}
740 }
741 
742 static void
743 update_vf(struct hfsc_class *cl, unsigned int len, u64 cur_time)
744 {
745 	u64 f; /* , myf_bound, delta; */
746 	int go_passive = 0;
747 
748 	if (cl->qdisc->q.qlen == 0 && cl->cl_flags & HFSC_FSC)
749 		go_passive = 1;
750 
751 	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
752 		cl->cl_total += len;
753 
754 		if (!(cl->cl_flags & HFSC_FSC) || cl->cl_nactive == 0)
755 			continue;
756 
757 		if (go_passive && --cl->cl_nactive == 0)
758 			go_passive = 1;
759 		else
760 			go_passive = 0;
761 
762 		/* update vt */
763 		cl->cl_vt = rtsc_y2x(&cl->cl_virtual, cl->cl_total) + cl->cl_vtadj;
764 
765 		/*
766 		 * if vt of the class is smaller than cvtmin,
767 		 * the class was skipped in the past due to non-fit.
768 		 * if so, we need to adjust vtadj.
769 		 */
770 		if (cl->cl_vt < cl->cl_parent->cl_cvtmin) {
771 			cl->cl_vtadj += cl->cl_parent->cl_cvtmin - cl->cl_vt;
772 			cl->cl_vt = cl->cl_parent->cl_cvtmin;
773 		}
774 
775 		if (go_passive) {
776 			/* no more active child, going passive */
777 
778 			/* update cvtoff of the parent class */
779 			if (cl->cl_vt > cl->cl_parent->cl_cvtoff)
780 				cl->cl_parent->cl_cvtoff = cl->cl_vt;
781 
782 			/* remove this class from the vt tree */
783 			vttree_remove(cl);
784 
785 			cftree_remove(cl);
786 			update_cfmin(cl->cl_parent);
787 
788 			continue;
789 		}
790 
791 		/* update the vt tree */
792 		vttree_update(cl);
793 
794 		/* update f */
795 		if (cl->cl_flags & HFSC_USC) {
796 			cl->cl_myf = rtsc_y2x(&cl->cl_ulimit, cl->cl_total);
797 #if 0
798 			cl->cl_myf = cl->cl_myfadj + rtsc_y2x(&cl->cl_ulimit,
799 							      cl->cl_total);
800 			/*
801 			 * This code causes classes to stay way under their
802 			 * limit when multiple classes are used at gigabit
803 			 * speed. needs investigation. -kaber
804 			 */
805 			/*
806 			 * if myf lags behind by more than one clock tick
807 			 * from the current time, adjust myfadj to prevent
808 			 * a rate-limited class from going greedy.
809 			 * in a steady state under rate-limiting, myf
810 			 * fluctuates within one clock tick.
811 			 */
812 			myf_bound = cur_time - PSCHED_JIFFIE2US(1);
813 			if (cl->cl_myf < myf_bound) {
814 				delta = cur_time - cl->cl_myf;
815 				cl->cl_myfadj += delta;
816 				cl->cl_myf += delta;
817 			}
818 #endif
819 		}
820 
821 		f = max(cl->cl_myf, cl->cl_cfmin);
822 		if (f != cl->cl_f) {
823 			cl->cl_f = f;
824 			cftree_update(cl);
825 			update_cfmin(cl->cl_parent);
826 		}
827 	}
828 }
829 
830 static unsigned int
831 qdisc_peek_len(struct Qdisc *sch)
832 {
833 	struct sk_buff *skb;
834 	unsigned int len;
835 
836 	skb = sch->ops->peek(sch);
837 	if (unlikely(skb == NULL)) {
838 		qdisc_warn_nonwc("qdisc_peek_len", sch);
839 		return 0;
840 	}
841 	len = qdisc_pkt_len(skb);
842 
843 	return len;
844 }
845 
846 static void
847 hfsc_adjust_levels(struct hfsc_class *cl)
848 {
849 	struct hfsc_class *p;
850 	unsigned int level;
851 
852 	do {
853 		level = 0;
854 		list_for_each_entry(p, &cl->children, siblings) {
855 			if (p->level >= level)
856 				level = p->level + 1;
857 		}
858 		cl->level = level;
859 	} while ((cl = cl->cl_parent) != NULL);
860 }
861 
862 static inline struct hfsc_class *
863 hfsc_find_class(u32 classid, struct Qdisc *sch)
864 {
865 	struct hfsc_sched *q = qdisc_priv(sch);
866 	struct Qdisc_class_common *clc;
867 
868 	clc = qdisc_class_find(&q->clhash, classid);
869 	if (clc == NULL)
870 		return NULL;
871 	return container_of(clc, struct hfsc_class, cl_common);
872 }
873 
874 static void
875 hfsc_change_rsc(struct hfsc_class *cl, struct tc_service_curve *rsc,
876 		u64 cur_time)
877 {
878 	sc2isc(rsc, &cl->cl_rsc);
879 	rtsc_init(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);
880 	cl->cl_eligible = cl->cl_deadline;
881 	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
882 		cl->cl_eligible.dx = 0;
883 		cl->cl_eligible.dy = 0;
884 	}
885 	cl->cl_flags |= HFSC_RSC;
886 }
887 
888 static void
889 hfsc_change_fsc(struct hfsc_class *cl, struct tc_service_curve *fsc)
890 {
891 	sc2isc(fsc, &cl->cl_fsc);
892 	rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
893 	cl->cl_flags |= HFSC_FSC;
894 }
895 
896 static void
897 hfsc_change_usc(struct hfsc_class *cl, struct tc_service_curve *usc,
898 		u64 cur_time)
899 {
900 	sc2isc(usc, &cl->cl_usc);
901 	rtsc_init(&cl->cl_ulimit, &cl->cl_usc, cur_time, cl->cl_total);
902 	cl->cl_flags |= HFSC_USC;
903 }
904 
905 static void
906 hfsc_upgrade_rt(struct hfsc_class *cl)
907 {
908 	cl->cl_fsc = cl->cl_rsc;
909 	rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
910 	cl->cl_flags |= HFSC_FSC;
911 }
912 
913 static const struct nla_policy hfsc_policy[TCA_HFSC_MAX + 1] = {
914 	[TCA_HFSC_RSC]	= { .len = sizeof(struct tc_service_curve) },
915 	[TCA_HFSC_FSC]	= { .len = sizeof(struct tc_service_curve) },
916 	[TCA_HFSC_USC]	= { .len = sizeof(struct tc_service_curve) },
917 };
918 
919 static int
920 hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
921 		  struct nlattr **tca, unsigned long *arg,
922 		  struct netlink_ext_ack *extack)
923 {
924 	struct hfsc_sched *q = qdisc_priv(sch);
925 	struct hfsc_class *cl = (struct hfsc_class *)*arg;
926 	struct hfsc_class *parent = NULL;
927 	struct nlattr *opt = tca[TCA_OPTIONS];
928 	struct nlattr *tb[TCA_HFSC_MAX + 1];
929 	struct tc_service_curve *rsc = NULL, *fsc = NULL, *usc = NULL;
930 	u64 cur_time;
931 	int err;
932 
933 	if (opt == NULL)
934 		return -EINVAL;
935 
936 	err = nla_parse_nested_deprecated(tb, TCA_HFSC_MAX, opt, hfsc_policy,
937 					  NULL);
938 	if (err < 0)
939 		return err;
940 
941 	if (tb[TCA_HFSC_RSC]) {
942 		rsc = nla_data(tb[TCA_HFSC_RSC]);
943 		if (rsc->m1 == 0 && rsc->m2 == 0)
944 			rsc = NULL;
945 	}
946 
947 	if (tb[TCA_HFSC_FSC]) {
948 		fsc = nla_data(tb[TCA_HFSC_FSC]);
949 		if (fsc->m1 == 0 && fsc->m2 == 0)
950 			fsc = NULL;
951 	}
952 
953 	if (tb[TCA_HFSC_USC]) {
954 		usc = nla_data(tb[TCA_HFSC_USC]);
955 		if (usc->m1 == 0 && usc->m2 == 0)
956 			usc = NULL;
957 	}
958 
959 	if (cl != NULL) {
960 		int old_flags;
961 
962 		if (parentid) {
963 			if (cl->cl_parent &&
964 			    cl->cl_parent->cl_common.classid != parentid)
965 				return -EINVAL;
966 			if (cl->cl_parent == NULL && parentid != TC_H_ROOT)
967 				return -EINVAL;
968 		}
969 		cur_time = psched_get_time();
970 
971 		if (tca[TCA_RATE]) {
972 			err = gen_replace_estimator(&cl->bstats, NULL,
973 						    &cl->rate_est,
974 						    NULL,
975 						    true,
976 						    tca[TCA_RATE]);
977 			if (err)
978 				return err;
979 		}
980 
981 		sch_tree_lock(sch);
982 		old_flags = cl->cl_flags;
983 
984 		if (rsc != NULL)
985 			hfsc_change_rsc(cl, rsc, cur_time);
986 		if (fsc != NULL)
987 			hfsc_change_fsc(cl, fsc);
988 		if (usc != NULL)
989 			hfsc_change_usc(cl, usc, cur_time);
990 
991 		if (cl->qdisc->q.qlen != 0) {
992 			int len = qdisc_peek_len(cl->qdisc);
993 
994 			if (cl->cl_flags & HFSC_RSC) {
995 				if (old_flags & HFSC_RSC)
996 					update_ed(cl, len);
997 				else
998 					init_ed(cl, len);
999 			}
1000 
1001 			if (cl->cl_flags & HFSC_FSC) {
1002 				if (old_flags & HFSC_FSC)
1003 					update_vf(cl, 0, cur_time);
1004 				else
1005 					init_vf(cl, len);
1006 			}
1007 		}
1008 		sch_tree_unlock(sch);
1009 
1010 		return 0;
1011 	}
1012 
1013 	if (parentid == TC_H_ROOT)
1014 		return -EEXIST;
1015 
1016 	parent = &q->root;
1017 	if (parentid) {
1018 		parent = hfsc_find_class(parentid, sch);
1019 		if (parent == NULL)
1020 			return -ENOENT;
1021 	}
1022 
1023 	if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0)
1024 		return -EINVAL;
1025 	if (hfsc_find_class(classid, sch))
1026 		return -EEXIST;
1027 
1028 	if (rsc == NULL && fsc == NULL)
1029 		return -EINVAL;
1030 
1031 	cl = kzalloc(sizeof(struct hfsc_class), GFP_KERNEL);
1032 	if (cl == NULL)
1033 		return -ENOBUFS;
1034 
1035 	err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
1036 	if (err) {
1037 		kfree(cl);
1038 		return err;
1039 	}
1040 
1041 	if (tca[TCA_RATE]) {
1042 		err = gen_new_estimator(&cl->bstats, NULL, &cl->rate_est,
1043 					NULL, true, tca[TCA_RATE]);
1044 		if (err) {
1045 			tcf_block_put(cl->block);
1046 			kfree(cl);
1047 			return err;
1048 		}
1049 	}
1050 
1051 	if (rsc != NULL)
1052 		hfsc_change_rsc(cl, rsc, 0);
1053 	if (fsc != NULL)
1054 		hfsc_change_fsc(cl, fsc);
1055 	if (usc != NULL)
1056 		hfsc_change_usc(cl, usc, 0);
1057 
1058 	cl->cl_common.classid = classid;
1059 	cl->sched     = q;
1060 	cl->cl_parent = parent;
1061 	cl->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1062 				      classid, NULL);
1063 	if (cl->qdisc == NULL)
1064 		cl->qdisc = &noop_qdisc;
1065 	else
1066 		qdisc_hash_add(cl->qdisc, true);
1067 	INIT_LIST_HEAD(&cl->children);
1068 	cl->vt_tree = RB_ROOT;
1069 	cl->cf_tree = RB_ROOT;
1070 
1071 	sch_tree_lock(sch);
1072 	/* Check if the inner class is a misconfigured 'rt' */
1073 	if (!(parent->cl_flags & HFSC_FSC) && parent != &q->root) {
1074 		NL_SET_ERR_MSG(extack,
1075 			       "Forced curve change on parent 'rt' to 'sc'");
1076 		hfsc_upgrade_rt(parent);
1077 	}
1078 	qdisc_class_hash_insert(&q->clhash, &cl->cl_common);
1079 	list_add_tail(&cl->siblings, &parent->children);
1080 	if (parent->level == 0)
1081 		qdisc_purge_queue(parent->qdisc);
1082 	hfsc_adjust_levels(parent);
1083 	sch_tree_unlock(sch);
1084 
1085 	qdisc_class_hash_grow(sch, &q->clhash);
1086 
1087 	*arg = (unsigned long)cl;
1088 	return 0;
1089 }
1090 
1091 static void
1092 hfsc_destroy_class(struct Qdisc *sch, struct hfsc_class *cl)
1093 {
1094 	struct hfsc_sched *q = qdisc_priv(sch);
1095 
1096 	tcf_block_put(cl->block);
1097 	qdisc_put(cl->qdisc);
1098 	gen_kill_estimator(&cl->rate_est);
1099 	if (cl != &q->root)
1100 		kfree(cl);
1101 }
1102 
1103 static int
1104 hfsc_delete_class(struct Qdisc *sch, unsigned long arg,
1105 		  struct netlink_ext_ack *extack)
1106 {
1107 	struct hfsc_sched *q = qdisc_priv(sch);
1108 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1109 
1110 	if (cl->level > 0 || qdisc_class_in_use(&cl->cl_common) ||
1111 	    cl == &q->root) {
1112 		NL_SET_ERR_MSG(extack, "HFSC class in use");
1113 		return -EBUSY;
1114 	}
1115 
1116 	sch_tree_lock(sch);
1117 
1118 	list_del(&cl->siblings);
1119 	hfsc_adjust_levels(cl->cl_parent);
1120 
1121 	qdisc_purge_queue(cl->qdisc);
1122 	qdisc_class_hash_remove(&q->clhash, &cl->cl_common);
1123 
1124 	sch_tree_unlock(sch);
1125 
1126 	hfsc_destroy_class(sch, cl);
1127 	return 0;
1128 }
1129 
1130 static struct hfsc_class *
1131 hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
1132 {
1133 	struct hfsc_sched *q = qdisc_priv(sch);
1134 	struct hfsc_class *head, *cl;
1135 	struct tcf_result res;
1136 	struct tcf_proto *tcf;
1137 	int result;
1138 
1139 	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0 &&
1140 	    (cl = hfsc_find_class(skb->priority, sch)) != NULL)
1141 		if (cl->level == 0)
1142 			return cl;
1143 
1144 	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
1145 	head = &q->root;
1146 	tcf = rcu_dereference_bh(q->root.filter_list);
1147 	while (tcf && (result = tcf_classify(skb, NULL, tcf, &res, false)) >= 0) {
1148 #ifdef CONFIG_NET_CLS_ACT
1149 		switch (result) {
1150 		case TC_ACT_QUEUED:
1151 		case TC_ACT_STOLEN:
1152 		case TC_ACT_TRAP:
1153 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
1154 			fallthrough;
1155 		case TC_ACT_SHOT:
1156 			return NULL;
1157 		}
1158 #endif
1159 		cl = (struct hfsc_class *)res.class;
1160 		if (!cl) {
1161 			cl = hfsc_find_class(res.classid, sch);
1162 			if (!cl)
1163 				break; /* filter selected invalid classid */
1164 			if (cl->level >= head->level)
1165 				break; /* filter may only point downwards */
1166 		}
1167 
1168 		if (cl->level == 0)
1169 			return cl; /* hit leaf class */
1170 
1171 		/* apply inner filter chain */
1172 		tcf = rcu_dereference_bh(cl->filter_list);
1173 		head = cl;
1174 	}
1175 
1176 	/* classification failed, try default class */
1177 	cl = hfsc_find_class(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
1178 	if (cl == NULL || cl->level > 0)
1179 		return NULL;
1180 
1181 	return cl;
1182 }
1183 
1184 static int
1185 hfsc_graft_class(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1186 		 struct Qdisc **old, struct netlink_ext_ack *extack)
1187 {
1188 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1189 
1190 	if (cl->level > 0)
1191 		return -EINVAL;
1192 	if (new == NULL) {
1193 		new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1194 					cl->cl_common.classid, NULL);
1195 		if (new == NULL)
1196 			new = &noop_qdisc;
1197 	}
1198 
1199 	*old = qdisc_replace(sch, new, &cl->qdisc);
1200 	return 0;
1201 }
1202 
1203 static struct Qdisc *
1204 hfsc_class_leaf(struct Qdisc *sch, unsigned long arg)
1205 {
1206 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1207 
1208 	if (cl->level == 0)
1209 		return cl->qdisc;
1210 
1211 	return NULL;
1212 }
1213 
1214 static void
1215 hfsc_qlen_notify(struct Qdisc *sch, unsigned long arg)
1216 {
1217 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1218 
1219 	/* vttree is now handled in update_vf() so that update_vf(cl, 0, 0)
1220 	 * needs to be called explicitly to remove a class from vttree.
1221 	 */
1222 	update_vf(cl, 0, 0);
1223 	if (cl->cl_flags & HFSC_RSC)
1224 		eltree_remove(cl);
1225 }
1226 
1227 static unsigned long
1228 hfsc_search_class(struct Qdisc *sch, u32 classid)
1229 {
1230 	return (unsigned long)hfsc_find_class(classid, sch);
1231 }
1232 
1233 static unsigned long
1234 hfsc_bind_tcf(struct Qdisc *sch, unsigned long parent, u32 classid)
1235 {
1236 	struct hfsc_class *p = (struct hfsc_class *)parent;
1237 	struct hfsc_class *cl = hfsc_find_class(classid, sch);
1238 
1239 	if (cl != NULL) {
1240 		if (p != NULL && p->level <= cl->level)
1241 			return 0;
1242 		qdisc_class_get(&cl->cl_common);
1243 	}
1244 
1245 	return (unsigned long)cl;
1246 }
1247 
1248 static void
1249 hfsc_unbind_tcf(struct Qdisc *sch, unsigned long arg)
1250 {
1251 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1252 
1253 	qdisc_class_put(&cl->cl_common);
1254 }
1255 
1256 static struct tcf_block *hfsc_tcf_block(struct Qdisc *sch, unsigned long arg,
1257 					struct netlink_ext_ack *extack)
1258 {
1259 	struct hfsc_sched *q = qdisc_priv(sch);
1260 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1261 
1262 	if (cl == NULL)
1263 		cl = &q->root;
1264 
1265 	return cl->block;
1266 }
1267 
1268 static int
1269 hfsc_dump_sc(struct sk_buff *skb, int attr, struct internal_sc *sc)
1270 {
1271 	struct tc_service_curve tsc;
1272 
1273 	tsc.m1 = sm2m(sc->sm1);
1274 	tsc.d  = dx2d(sc->dx);
1275 	tsc.m2 = sm2m(sc->sm2);
1276 	if (nla_put(skb, attr, sizeof(tsc), &tsc))
1277 		goto nla_put_failure;
1278 
1279 	return skb->len;
1280 
1281  nla_put_failure:
1282 	return -1;
1283 }
1284 
1285 static int
1286 hfsc_dump_curves(struct sk_buff *skb, struct hfsc_class *cl)
1287 {
1288 	if ((cl->cl_flags & HFSC_RSC) &&
1289 	    (hfsc_dump_sc(skb, TCA_HFSC_RSC, &cl->cl_rsc) < 0))
1290 		goto nla_put_failure;
1291 
1292 	if ((cl->cl_flags & HFSC_FSC) &&
1293 	    (hfsc_dump_sc(skb, TCA_HFSC_FSC, &cl->cl_fsc) < 0))
1294 		goto nla_put_failure;
1295 
1296 	if ((cl->cl_flags & HFSC_USC) &&
1297 	    (hfsc_dump_sc(skb, TCA_HFSC_USC, &cl->cl_usc) < 0))
1298 		goto nla_put_failure;
1299 
1300 	return skb->len;
1301 
1302  nla_put_failure:
1303 	return -1;
1304 }
1305 
1306 static int
1307 hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,
1308 		struct tcmsg *tcm)
1309 {
1310 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1311 	struct nlattr *nest;
1312 
1313 	tcm->tcm_parent = cl->cl_parent ? cl->cl_parent->cl_common.classid :
1314 					  TC_H_ROOT;
1315 	tcm->tcm_handle = cl->cl_common.classid;
1316 	if (cl->level == 0)
1317 		tcm->tcm_info = cl->qdisc->handle;
1318 
1319 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
1320 	if (nest == NULL)
1321 		goto nla_put_failure;
1322 	if (hfsc_dump_curves(skb, cl) < 0)
1323 		goto nla_put_failure;
1324 	return nla_nest_end(skb, nest);
1325 
1326  nla_put_failure:
1327 	nla_nest_cancel(skb, nest);
1328 	return -EMSGSIZE;
1329 }
1330 
1331 static int
1332 hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
1333 	struct gnet_dump *d)
1334 {
1335 	struct hfsc_class *cl = (struct hfsc_class *)arg;
1336 	struct tc_hfsc_stats xstats;
1337 	__u32 qlen;
1338 
1339 	qdisc_qstats_qlen_backlog(cl->qdisc, &qlen, &cl->qstats.backlog);
1340 	xstats.level   = cl->level;
1341 	xstats.period  = cl->cl_vtperiod;
1342 	xstats.work    = cl->cl_total;
1343 	xstats.rtwork  = cl->cl_cumul;
1344 
1345 	if (gnet_stats_copy_basic(d, NULL, &cl->bstats, true) < 0 ||
1346 	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1347 	    gnet_stats_copy_queue(d, NULL, &cl->qstats, qlen) < 0)
1348 		return -1;
1349 
1350 	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
1351 }
1352 
1353 
1354 
1355 static void
1356 hfsc_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1357 {
1358 	struct hfsc_sched *q = qdisc_priv(sch);
1359 	struct hfsc_class *cl;
1360 	unsigned int i;
1361 
1362 	if (arg->stop)
1363 		return;
1364 
1365 	for (i = 0; i < q->clhash.hashsize; i++) {
1366 		hlist_for_each_entry(cl, &q->clhash.hash[i],
1367 				     cl_common.hnode) {
1368 			if (!tc_qdisc_stats_dump(sch, (unsigned long)cl, arg))
1369 				return;
1370 		}
1371 	}
1372 }
1373 
1374 static void
1375 hfsc_schedule_watchdog(struct Qdisc *sch)
1376 {
1377 	struct hfsc_sched *q = qdisc_priv(sch);
1378 	struct hfsc_class *cl;
1379 	u64 next_time = 0;
1380 
1381 	cl = eltree_get_minel(q);
1382 	if (cl)
1383 		next_time = cl->cl_e;
1384 	if (q->root.cl_cfmin != 0) {
1385 		if (next_time == 0 || next_time > q->root.cl_cfmin)
1386 			next_time = q->root.cl_cfmin;
1387 	}
1388 	if (next_time)
1389 		qdisc_watchdog_schedule(&q->watchdog, next_time);
1390 }
1391 
1392 static int
1393 hfsc_init_qdisc(struct Qdisc *sch, struct nlattr *opt,
1394 		struct netlink_ext_ack *extack)
1395 {
1396 	struct hfsc_sched *q = qdisc_priv(sch);
1397 	struct tc_hfsc_qopt *qopt;
1398 	int err;
1399 
1400 	qdisc_watchdog_init(&q->watchdog, sch);
1401 
1402 	if (!opt || nla_len(opt) < sizeof(*qopt))
1403 		return -EINVAL;
1404 	qopt = nla_data(opt);
1405 
1406 	q->defcls = qopt->defcls;
1407 	err = qdisc_class_hash_init(&q->clhash);
1408 	if (err < 0)
1409 		return err;
1410 	q->eligible = RB_ROOT;
1411 
1412 	err = tcf_block_get(&q->root.block, &q->root.filter_list, sch, extack);
1413 	if (err)
1414 		return err;
1415 
1416 	gnet_stats_basic_sync_init(&q->root.bstats);
1417 	q->root.cl_common.classid = sch->handle;
1418 	q->root.sched   = q;
1419 	q->root.qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1420 					  sch->handle, NULL);
1421 	if (q->root.qdisc == NULL)
1422 		q->root.qdisc = &noop_qdisc;
1423 	else
1424 		qdisc_hash_add(q->root.qdisc, true);
1425 	INIT_LIST_HEAD(&q->root.children);
1426 	q->root.vt_tree = RB_ROOT;
1427 	q->root.cf_tree = RB_ROOT;
1428 
1429 	qdisc_class_hash_insert(&q->clhash, &q->root.cl_common);
1430 	qdisc_class_hash_grow(sch, &q->clhash);
1431 
1432 	return 0;
1433 }
1434 
1435 static int
1436 hfsc_change_qdisc(struct Qdisc *sch, struct nlattr *opt,
1437 		  struct netlink_ext_ack *extack)
1438 {
1439 	struct hfsc_sched *q = qdisc_priv(sch);
1440 	struct tc_hfsc_qopt *qopt;
1441 
1442 	if (nla_len(opt) < sizeof(*qopt))
1443 		return -EINVAL;
1444 	qopt = nla_data(opt);
1445 
1446 	sch_tree_lock(sch);
1447 	q->defcls = qopt->defcls;
1448 	sch_tree_unlock(sch);
1449 
1450 	return 0;
1451 }
1452 
1453 static void
1454 hfsc_reset_class(struct hfsc_class *cl)
1455 {
1456 	cl->cl_total        = 0;
1457 	cl->cl_cumul        = 0;
1458 	cl->cl_d            = 0;
1459 	cl->cl_e            = 0;
1460 	cl->cl_vt           = 0;
1461 	cl->cl_vtadj        = 0;
1462 	cl->cl_cvtmin       = 0;
1463 	cl->cl_cvtoff       = 0;
1464 	cl->cl_vtperiod     = 0;
1465 	cl->cl_parentperiod = 0;
1466 	cl->cl_f            = 0;
1467 	cl->cl_myf          = 0;
1468 	cl->cl_cfmin        = 0;
1469 	cl->cl_nactive      = 0;
1470 
1471 	cl->vt_tree = RB_ROOT;
1472 	cl->cf_tree = RB_ROOT;
1473 	qdisc_reset(cl->qdisc);
1474 
1475 	if (cl->cl_flags & HFSC_RSC)
1476 		rtsc_init(&cl->cl_deadline, &cl->cl_rsc, 0, 0);
1477 	if (cl->cl_flags & HFSC_FSC)
1478 		rtsc_init(&cl->cl_virtual, &cl->cl_fsc, 0, 0);
1479 	if (cl->cl_flags & HFSC_USC)
1480 		rtsc_init(&cl->cl_ulimit, &cl->cl_usc, 0, 0);
1481 }
1482 
1483 static void
1484 hfsc_reset_qdisc(struct Qdisc *sch)
1485 {
1486 	struct hfsc_sched *q = qdisc_priv(sch);
1487 	struct hfsc_class *cl;
1488 	unsigned int i;
1489 
1490 	for (i = 0; i < q->clhash.hashsize; i++) {
1491 		hlist_for_each_entry(cl, &q->clhash.hash[i], cl_common.hnode)
1492 			hfsc_reset_class(cl);
1493 	}
1494 	q->eligible = RB_ROOT;
1495 	qdisc_watchdog_cancel(&q->watchdog);
1496 }
1497 
1498 static void
1499 hfsc_destroy_qdisc(struct Qdisc *sch)
1500 {
1501 	struct hfsc_sched *q = qdisc_priv(sch);
1502 	struct hlist_node *next;
1503 	struct hfsc_class *cl;
1504 	unsigned int i;
1505 
1506 	for (i = 0; i < q->clhash.hashsize; i++) {
1507 		hlist_for_each_entry(cl, &q->clhash.hash[i], cl_common.hnode) {
1508 			tcf_block_put(cl->block);
1509 			cl->block = NULL;
1510 		}
1511 	}
1512 	for (i = 0; i < q->clhash.hashsize; i++) {
1513 		hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
1514 					  cl_common.hnode)
1515 			hfsc_destroy_class(sch, cl);
1516 	}
1517 	qdisc_class_hash_destroy(&q->clhash);
1518 	qdisc_watchdog_cancel(&q->watchdog);
1519 }
1520 
1521 static int
1522 hfsc_dump_qdisc(struct Qdisc *sch, struct sk_buff *skb)
1523 {
1524 	struct hfsc_sched *q = qdisc_priv(sch);
1525 	unsigned char *b = skb_tail_pointer(skb);
1526 	struct tc_hfsc_qopt qopt;
1527 
1528 	qopt.defcls = q->defcls;
1529 	if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1530 		goto nla_put_failure;
1531 	return skb->len;
1532 
1533  nla_put_failure:
1534 	nlmsg_trim(skb, b);
1535 	return -1;
1536 }
1537 
1538 static int
1539 hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
1540 {
1541 	unsigned int len = qdisc_pkt_len(skb);
1542 	struct hfsc_class *cl;
1543 	int err;
1544 	bool first;
1545 
1546 	cl = hfsc_classify(skb, sch, &err);
1547 	if (cl == NULL) {
1548 		if (err & __NET_XMIT_BYPASS)
1549 			qdisc_qstats_drop(sch);
1550 		__qdisc_drop(skb, to_free);
1551 		return err;
1552 	}
1553 
1554 	first = !cl->qdisc->q.qlen;
1555 	err = qdisc_enqueue(skb, cl->qdisc, to_free);
1556 	if (unlikely(err != NET_XMIT_SUCCESS)) {
1557 		if (net_xmit_drop_count(err)) {
1558 			cl->qstats.drops++;
1559 			qdisc_qstats_drop(sch);
1560 		}
1561 		return err;
1562 	}
1563 
1564 	if (first) {
1565 		if (cl->cl_flags & HFSC_RSC)
1566 			init_ed(cl, len);
1567 		if (cl->cl_flags & HFSC_FSC)
1568 			init_vf(cl, len);
1569 		/*
1570 		 * If this is the first packet, isolate the head so an eventual
1571 		 * head drop before the first dequeue operation has no chance
1572 		 * to invalidate the deadline.
1573 		 */
1574 		if (cl->cl_flags & HFSC_RSC)
1575 			cl->qdisc->ops->peek(cl->qdisc);
1576 
1577 	}
1578 
1579 	sch->qstats.backlog += len;
1580 	sch->q.qlen++;
1581 
1582 	return NET_XMIT_SUCCESS;
1583 }
1584 
1585 static struct sk_buff *
1586 hfsc_dequeue(struct Qdisc *sch)
1587 {
1588 	struct hfsc_sched *q = qdisc_priv(sch);
1589 	struct hfsc_class *cl;
1590 	struct sk_buff *skb;
1591 	u64 cur_time;
1592 	unsigned int next_len;
1593 	int realtime = 0;
1594 
1595 	if (sch->q.qlen == 0)
1596 		return NULL;
1597 
1598 	cur_time = psched_get_time();
1599 
1600 	/*
1601 	 * if there are eligible classes, use real-time criteria.
1602 	 * find the class with the minimum deadline among
1603 	 * the eligible classes.
1604 	 */
1605 	cl = eltree_get_mindl(q, cur_time);
1606 	if (cl) {
1607 		realtime = 1;
1608 	} else {
1609 		/*
1610 		 * use link-sharing criteria
1611 		 * get the class with the minimum vt in the hierarchy
1612 		 */
1613 		cl = vttree_get_minvt(&q->root, cur_time);
1614 		if (cl == NULL) {
1615 			qdisc_qstats_overlimit(sch);
1616 			hfsc_schedule_watchdog(sch);
1617 			return NULL;
1618 		}
1619 	}
1620 
1621 	skb = qdisc_dequeue_peeked(cl->qdisc);
1622 	if (skb == NULL) {
1623 		qdisc_warn_nonwc("HFSC", cl->qdisc);
1624 		return NULL;
1625 	}
1626 
1627 	bstats_update(&cl->bstats, skb);
1628 	update_vf(cl, qdisc_pkt_len(skb), cur_time);
1629 	if (realtime)
1630 		cl->cl_cumul += qdisc_pkt_len(skb);
1631 
1632 	if (cl->cl_flags & HFSC_RSC) {
1633 		if (cl->qdisc->q.qlen != 0) {
1634 			/* update ed */
1635 			next_len = qdisc_peek_len(cl->qdisc);
1636 			if (realtime)
1637 				update_ed(cl, next_len);
1638 			else
1639 				update_d(cl, next_len);
1640 		} else {
1641 			/* the class becomes passive */
1642 			eltree_remove(cl);
1643 		}
1644 	}
1645 
1646 	qdisc_bstats_update(sch, skb);
1647 	qdisc_qstats_backlog_dec(sch, skb);
1648 	sch->q.qlen--;
1649 
1650 	return skb;
1651 }
1652 
1653 static const struct Qdisc_class_ops hfsc_class_ops = {
1654 	.change		= hfsc_change_class,
1655 	.delete		= hfsc_delete_class,
1656 	.graft		= hfsc_graft_class,
1657 	.leaf		= hfsc_class_leaf,
1658 	.qlen_notify	= hfsc_qlen_notify,
1659 	.find		= hfsc_search_class,
1660 	.bind_tcf	= hfsc_bind_tcf,
1661 	.unbind_tcf	= hfsc_unbind_tcf,
1662 	.tcf_block	= hfsc_tcf_block,
1663 	.dump		= hfsc_dump_class,
1664 	.dump_stats	= hfsc_dump_class_stats,
1665 	.walk		= hfsc_walk
1666 };
1667 
1668 static struct Qdisc_ops hfsc_qdisc_ops __read_mostly = {
1669 	.id		= "hfsc",
1670 	.init		= hfsc_init_qdisc,
1671 	.change		= hfsc_change_qdisc,
1672 	.reset		= hfsc_reset_qdisc,
1673 	.destroy	= hfsc_destroy_qdisc,
1674 	.dump		= hfsc_dump_qdisc,
1675 	.enqueue	= hfsc_enqueue,
1676 	.dequeue	= hfsc_dequeue,
1677 	.peek		= qdisc_peek_dequeued,
1678 	.cl_ops		= &hfsc_class_ops,
1679 	.priv_size	= sizeof(struct hfsc_sched),
1680 	.owner		= THIS_MODULE
1681 };
1682 
1683 static int __init
1684 hfsc_init(void)
1685 {
1686 	return register_qdisc(&hfsc_qdisc_ops);
1687 }
1688 
1689 static void __exit
1690 hfsc_cleanup(void)
1691 {
1692 	unregister_qdisc(&hfsc_qdisc_ops);
1693 }
1694 
1695 MODULE_LICENSE("GPL");
1696 module_init(hfsc_init);
1697 module_exit(hfsc_cleanup);
1698