1// SPDX-License-Identifier: GPL-2.0
2/*
3 * DAMON sysfs Interface
4 *
5 * Copyright (c) 2022 SeongJae Park <sj@kernel.org>
6 */
7
8#include <linux/pid.h>
9#include <linux/sched.h>
10#include <linux/slab.h>
11
12#include "sysfs-common.h"
13
14/*
15 * init region directory
16 */
17
18struct damon_sysfs_region {
19	struct kobject kobj;
20	struct damon_addr_range ar;
21};
22
23static struct damon_sysfs_region *damon_sysfs_region_alloc(void)
24{
25	return kzalloc(sizeof(struct damon_sysfs_region), GFP_KERNEL);
26}
27
28static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
29		char *buf)
30{
31	struct damon_sysfs_region *region = container_of(kobj,
32			struct damon_sysfs_region, kobj);
33
34	return sysfs_emit(buf, "%lu\n", region->ar.start);
35}
36
37static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
38		const char *buf, size_t count)
39{
40	struct damon_sysfs_region *region = container_of(kobj,
41			struct damon_sysfs_region, kobj);
42	int err = kstrtoul(buf, 0, &region->ar.start);
43
44	return err ? err : count;
45}
46
47static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
48		char *buf)
49{
50	struct damon_sysfs_region *region = container_of(kobj,
51			struct damon_sysfs_region, kobj);
52
53	return sysfs_emit(buf, "%lu\n", region->ar.end);
54}
55
56static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
57		const char *buf, size_t count)
58{
59	struct damon_sysfs_region *region = container_of(kobj,
60			struct damon_sysfs_region, kobj);
61	int err = kstrtoul(buf, 0, &region->ar.end);
62
63	return err ? err : count;
64}
65
66static void damon_sysfs_region_release(struct kobject *kobj)
67{
68	kfree(container_of(kobj, struct damon_sysfs_region, kobj));
69}
70
71static struct kobj_attribute damon_sysfs_region_start_attr =
72		__ATTR_RW_MODE(start, 0600);
73
74static struct kobj_attribute damon_sysfs_region_end_attr =
75		__ATTR_RW_MODE(end, 0600);
76
77static struct attribute *damon_sysfs_region_attrs[] = {
78	&damon_sysfs_region_start_attr.attr,
79	&damon_sysfs_region_end_attr.attr,
80	NULL,
81};
82ATTRIBUTE_GROUPS(damon_sysfs_region);
83
84static const struct kobj_type damon_sysfs_region_ktype = {
85	.release = damon_sysfs_region_release,
86	.sysfs_ops = &kobj_sysfs_ops,
87	.default_groups = damon_sysfs_region_groups,
88};
89
90/*
91 * init_regions directory
92 */
93
94struct damon_sysfs_regions {
95	struct kobject kobj;
96	struct damon_sysfs_region **regions_arr;
97	int nr;
98};
99
100static struct damon_sysfs_regions *damon_sysfs_regions_alloc(void)
101{
102	return kzalloc(sizeof(struct damon_sysfs_regions), GFP_KERNEL);
103}
104
105static void damon_sysfs_regions_rm_dirs(struct damon_sysfs_regions *regions)
106{
107	struct damon_sysfs_region **regions_arr = regions->regions_arr;
108	int i;
109
110	for (i = 0; i < regions->nr; i++)
111		kobject_put(&regions_arr[i]->kobj);
112	regions->nr = 0;
113	kfree(regions_arr);
114	regions->regions_arr = NULL;
115}
116
117static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
118		int nr_regions)
119{
120	struct damon_sysfs_region **regions_arr, *region;
121	int err, i;
122
123	damon_sysfs_regions_rm_dirs(regions);
124	if (!nr_regions)
125		return 0;
126
127	regions_arr = kmalloc_array(nr_regions, sizeof(*regions_arr),
128			GFP_KERNEL | __GFP_NOWARN);
129	if (!regions_arr)
130		return -ENOMEM;
131	regions->regions_arr = regions_arr;
132
133	for (i = 0; i < nr_regions; i++) {
134		region = damon_sysfs_region_alloc();
135		if (!region) {
136			damon_sysfs_regions_rm_dirs(regions);
137			return -ENOMEM;
138		}
139
140		err = kobject_init_and_add(&region->kobj,
141				&damon_sysfs_region_ktype, &regions->kobj,
142				"%d", i);
143		if (err) {
144			kobject_put(&region->kobj);
145			damon_sysfs_regions_rm_dirs(regions);
146			return err;
147		}
148
149		regions_arr[i] = region;
150		regions->nr++;
151	}
152	return 0;
153}
154
155static ssize_t nr_regions_show(struct kobject *kobj,
156		struct kobj_attribute *attr, char *buf)
157{
158	struct damon_sysfs_regions *regions = container_of(kobj,
159			struct damon_sysfs_regions, kobj);
160
161	return sysfs_emit(buf, "%d\n", regions->nr);
162}
163
164static ssize_t nr_regions_store(struct kobject *kobj,
165		struct kobj_attribute *attr, const char *buf, size_t count)
166{
167	struct damon_sysfs_regions *regions;
168	int nr, err = kstrtoint(buf, 0, &nr);
169
170	if (err)
171		return err;
172	if (nr < 0)
173		return -EINVAL;
174
175	regions = container_of(kobj, struct damon_sysfs_regions, kobj);
176
177	if (!mutex_trylock(&damon_sysfs_lock))
178		return -EBUSY;
179	err = damon_sysfs_regions_add_dirs(regions, nr);
180	mutex_unlock(&damon_sysfs_lock);
181	if (err)
182		return err;
183
184	return count;
185}
186
187static void damon_sysfs_regions_release(struct kobject *kobj)
188{
189	kfree(container_of(kobj, struct damon_sysfs_regions, kobj));
190}
191
192static struct kobj_attribute damon_sysfs_regions_nr_attr =
193		__ATTR_RW_MODE(nr_regions, 0600);
194
195static struct attribute *damon_sysfs_regions_attrs[] = {
196	&damon_sysfs_regions_nr_attr.attr,
197	NULL,
198};
199ATTRIBUTE_GROUPS(damon_sysfs_regions);
200
201static const struct kobj_type damon_sysfs_regions_ktype = {
202	.release = damon_sysfs_regions_release,
203	.sysfs_ops = &kobj_sysfs_ops,
204	.default_groups = damon_sysfs_regions_groups,
205};
206
207/*
208 * target directory
209 */
210
211struct damon_sysfs_target {
212	struct kobject kobj;
213	struct damon_sysfs_regions *regions;
214	int pid;
215};
216
217static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
218{
219	return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL);
220}
221
222static int damon_sysfs_target_add_dirs(struct damon_sysfs_target *target)
223{
224	struct damon_sysfs_regions *regions = damon_sysfs_regions_alloc();
225	int err;
226
227	if (!regions)
228		return -ENOMEM;
229
230	err = kobject_init_and_add(&regions->kobj, &damon_sysfs_regions_ktype,
231			&target->kobj, "regions");
232	if (err)
233		kobject_put(&regions->kobj);
234	else
235		target->regions = regions;
236	return err;
237}
238
239static void damon_sysfs_target_rm_dirs(struct damon_sysfs_target *target)
240{
241	damon_sysfs_regions_rm_dirs(target->regions);
242	kobject_put(&target->regions->kobj);
243}
244
245static ssize_t pid_target_show(struct kobject *kobj,
246		struct kobj_attribute *attr, char *buf)
247{
248	struct damon_sysfs_target *target = container_of(kobj,
249			struct damon_sysfs_target, kobj);
250
251	return sysfs_emit(buf, "%d\n", target->pid);
252}
253
254static ssize_t pid_target_store(struct kobject *kobj,
255		struct kobj_attribute *attr, const char *buf, size_t count)
256{
257	struct damon_sysfs_target *target = container_of(kobj,
258			struct damon_sysfs_target, kobj);
259	int err = kstrtoint(buf, 0, &target->pid);
260
261	if (err)
262		return -EINVAL;
263	return count;
264}
265
266static void damon_sysfs_target_release(struct kobject *kobj)
267{
268	kfree(container_of(kobj, struct damon_sysfs_target, kobj));
269}
270
271static struct kobj_attribute damon_sysfs_target_pid_attr =
272		__ATTR_RW_MODE(pid_target, 0600);
273
274static struct attribute *damon_sysfs_target_attrs[] = {
275	&damon_sysfs_target_pid_attr.attr,
276	NULL,
277};
278ATTRIBUTE_GROUPS(damon_sysfs_target);
279
280static const struct kobj_type damon_sysfs_target_ktype = {
281	.release = damon_sysfs_target_release,
282	.sysfs_ops = &kobj_sysfs_ops,
283	.default_groups = damon_sysfs_target_groups,
284};
285
286/*
287 * targets directory
288 */
289
290struct damon_sysfs_targets {
291	struct kobject kobj;
292	struct damon_sysfs_target **targets_arr;
293	int nr;
294};
295
296static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
297{
298	return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL);
299}
300
301static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
302{
303	struct damon_sysfs_target **targets_arr = targets->targets_arr;
304	int i;
305
306	for (i = 0; i < targets->nr; i++) {
307		damon_sysfs_target_rm_dirs(targets_arr[i]);
308		kobject_put(&targets_arr[i]->kobj);
309	}
310	targets->nr = 0;
311	kfree(targets_arr);
312	targets->targets_arr = NULL;
313}
314
315static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
316		int nr_targets)
317{
318	struct damon_sysfs_target **targets_arr, *target;
319	int err, i;
320
321	damon_sysfs_targets_rm_dirs(targets);
322	if (!nr_targets)
323		return 0;
324
325	targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr),
326			GFP_KERNEL | __GFP_NOWARN);
327	if (!targets_arr)
328		return -ENOMEM;
329	targets->targets_arr = targets_arr;
330
331	for (i = 0; i < nr_targets; i++) {
332		target = damon_sysfs_target_alloc();
333		if (!target) {
334			damon_sysfs_targets_rm_dirs(targets);
335			return -ENOMEM;
336		}
337
338		err = kobject_init_and_add(&target->kobj,
339				&damon_sysfs_target_ktype, &targets->kobj,
340				"%d", i);
341		if (err)
342			goto out;
343
344		err = damon_sysfs_target_add_dirs(target);
345		if (err)
346			goto out;
347
348		targets_arr[i] = target;
349		targets->nr++;
350	}
351	return 0;
352
353out:
354	damon_sysfs_targets_rm_dirs(targets);
355	kobject_put(&target->kobj);
356	return err;
357}
358
359static ssize_t nr_targets_show(struct kobject *kobj,
360		struct kobj_attribute *attr, char *buf)
361{
362	struct damon_sysfs_targets *targets = container_of(kobj,
363			struct damon_sysfs_targets, kobj);
364
365	return sysfs_emit(buf, "%d\n", targets->nr);
366}
367
368static ssize_t nr_targets_store(struct kobject *kobj,
369		struct kobj_attribute *attr, const char *buf, size_t count)
370{
371	struct damon_sysfs_targets *targets;
372	int nr, err = kstrtoint(buf, 0, &nr);
373
374	if (err)
375		return err;
376	if (nr < 0)
377		return -EINVAL;
378
379	targets = container_of(kobj, struct damon_sysfs_targets, kobj);
380
381	if (!mutex_trylock(&damon_sysfs_lock))
382		return -EBUSY;
383	err = damon_sysfs_targets_add_dirs(targets, nr);
384	mutex_unlock(&damon_sysfs_lock);
385	if (err)
386		return err;
387
388	return count;
389}
390
391static void damon_sysfs_targets_release(struct kobject *kobj)
392{
393	kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
394}
395
396static struct kobj_attribute damon_sysfs_targets_nr_attr =
397		__ATTR_RW_MODE(nr_targets, 0600);
398
399static struct attribute *damon_sysfs_targets_attrs[] = {
400	&damon_sysfs_targets_nr_attr.attr,
401	NULL,
402};
403ATTRIBUTE_GROUPS(damon_sysfs_targets);
404
405static const struct kobj_type damon_sysfs_targets_ktype = {
406	.release = damon_sysfs_targets_release,
407	.sysfs_ops = &kobj_sysfs_ops,
408	.default_groups = damon_sysfs_targets_groups,
409};
410
411/*
412 * intervals directory
413 */
414
415struct damon_sysfs_intervals {
416	struct kobject kobj;
417	unsigned long sample_us;
418	unsigned long aggr_us;
419	unsigned long update_us;
420};
421
422static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
423		unsigned long sample_us, unsigned long aggr_us,
424		unsigned long update_us)
425{
426	struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals),
427			GFP_KERNEL);
428
429	if (!intervals)
430		return NULL;
431
432	intervals->kobj = (struct kobject){};
433	intervals->sample_us = sample_us;
434	intervals->aggr_us = aggr_us;
435	intervals->update_us = update_us;
436	return intervals;
437}
438
439static ssize_t sample_us_show(struct kobject *kobj,
440		struct kobj_attribute *attr, char *buf)
441{
442	struct damon_sysfs_intervals *intervals = container_of(kobj,
443			struct damon_sysfs_intervals, kobj);
444
445	return sysfs_emit(buf, "%lu\n", intervals->sample_us);
446}
447
448static ssize_t sample_us_store(struct kobject *kobj,
449		struct kobj_attribute *attr, const char *buf, size_t count)
450{
451	struct damon_sysfs_intervals *intervals = container_of(kobj,
452			struct damon_sysfs_intervals, kobj);
453	unsigned long us;
454	int err = kstrtoul(buf, 0, &us);
455
456	if (err)
457		return err;
458
459	intervals->sample_us = us;
460	return count;
461}
462
463static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
464		char *buf)
465{
466	struct damon_sysfs_intervals *intervals = container_of(kobj,
467			struct damon_sysfs_intervals, kobj);
468
469	return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
470}
471
472static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
473		const char *buf, size_t count)
474{
475	struct damon_sysfs_intervals *intervals = container_of(kobj,
476			struct damon_sysfs_intervals, kobj);
477	unsigned long us;
478	int err = kstrtoul(buf, 0, &us);
479
480	if (err)
481		return err;
482
483	intervals->aggr_us = us;
484	return count;
485}
486
487static ssize_t update_us_show(struct kobject *kobj,
488		struct kobj_attribute *attr, char *buf)
489{
490	struct damon_sysfs_intervals *intervals = container_of(kobj,
491			struct damon_sysfs_intervals, kobj);
492
493	return sysfs_emit(buf, "%lu\n", intervals->update_us);
494}
495
496static ssize_t update_us_store(struct kobject *kobj,
497		struct kobj_attribute *attr, const char *buf, size_t count)
498{
499	struct damon_sysfs_intervals *intervals = container_of(kobj,
500			struct damon_sysfs_intervals, kobj);
501	unsigned long us;
502	int err = kstrtoul(buf, 0, &us);
503
504	if (err)
505		return err;
506
507	intervals->update_us = us;
508	return count;
509}
510
511static void damon_sysfs_intervals_release(struct kobject *kobj)
512{
513	kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
514}
515
516static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
517		__ATTR_RW_MODE(sample_us, 0600);
518
519static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
520		__ATTR_RW_MODE(aggr_us, 0600);
521
522static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
523		__ATTR_RW_MODE(update_us, 0600);
524
525static struct attribute *damon_sysfs_intervals_attrs[] = {
526	&damon_sysfs_intervals_sample_us_attr.attr,
527	&damon_sysfs_intervals_aggr_us_attr.attr,
528	&damon_sysfs_intervals_update_us_attr.attr,
529	NULL,
530};
531ATTRIBUTE_GROUPS(damon_sysfs_intervals);
532
533static const struct kobj_type damon_sysfs_intervals_ktype = {
534	.release = damon_sysfs_intervals_release,
535	.sysfs_ops = &kobj_sysfs_ops,
536	.default_groups = damon_sysfs_intervals_groups,
537};
538
539/*
540 * monitoring_attrs directory
541 */
542
543struct damon_sysfs_attrs {
544	struct kobject kobj;
545	struct damon_sysfs_intervals *intervals;
546	struct damon_sysfs_ul_range *nr_regions_range;
547};
548
549static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
550{
551	struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
552
553	if (!attrs)
554		return NULL;
555	attrs->kobj = (struct kobject){};
556	return attrs;
557}
558
559static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
560{
561	struct damon_sysfs_intervals *intervals;
562	struct damon_sysfs_ul_range *nr_regions_range;
563	int err;
564
565	intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
566	if (!intervals)
567		return -ENOMEM;
568
569	err = kobject_init_and_add(&intervals->kobj,
570			&damon_sysfs_intervals_ktype, &attrs->kobj,
571			"intervals");
572	if (err)
573		goto put_intervals_out;
574	attrs->intervals = intervals;
575
576	nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
577	if (!nr_regions_range) {
578		err = -ENOMEM;
579		goto put_intervals_out;
580	}
581
582	err = kobject_init_and_add(&nr_regions_range->kobj,
583			&damon_sysfs_ul_range_ktype, &attrs->kobj,
584			"nr_regions");
585	if (err)
586		goto put_nr_regions_intervals_out;
587	attrs->nr_regions_range = nr_regions_range;
588	return 0;
589
590put_nr_regions_intervals_out:
591	kobject_put(&nr_regions_range->kobj);
592	attrs->nr_regions_range = NULL;
593put_intervals_out:
594	kobject_put(&intervals->kobj);
595	attrs->intervals = NULL;
596	return err;
597}
598
599static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
600{
601	kobject_put(&attrs->nr_regions_range->kobj);
602	kobject_put(&attrs->intervals->kobj);
603}
604
605static void damon_sysfs_attrs_release(struct kobject *kobj)
606{
607	kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
608}
609
610static struct attribute *damon_sysfs_attrs_attrs[] = {
611	NULL,
612};
613ATTRIBUTE_GROUPS(damon_sysfs_attrs);
614
615static const struct kobj_type damon_sysfs_attrs_ktype = {
616	.release = damon_sysfs_attrs_release,
617	.sysfs_ops = &kobj_sysfs_ops,
618	.default_groups = damon_sysfs_attrs_groups,
619};
620
621/*
622 * context directory
623 */
624
625/* This should match with enum damon_ops_id */
626static const char * const damon_sysfs_ops_strs[] = {
627	"vaddr",
628	"fvaddr",
629	"paddr",
630};
631
632struct damon_sysfs_context {
633	struct kobject kobj;
634	enum damon_ops_id ops_id;
635	struct damon_sysfs_attrs *attrs;
636	struct damon_sysfs_targets *targets;
637	struct damon_sysfs_schemes *schemes;
638};
639
640static struct damon_sysfs_context *damon_sysfs_context_alloc(
641		enum damon_ops_id ops_id)
642{
643	struct damon_sysfs_context *context = kmalloc(sizeof(*context),
644				GFP_KERNEL);
645
646	if (!context)
647		return NULL;
648	context->kobj = (struct kobject){};
649	context->ops_id = ops_id;
650	return context;
651}
652
653static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
654{
655	struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
656	int err;
657
658	if (!attrs)
659		return -ENOMEM;
660	err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
661			&context->kobj, "monitoring_attrs");
662	if (err)
663		goto out;
664	err = damon_sysfs_attrs_add_dirs(attrs);
665	if (err)
666		goto out;
667	context->attrs = attrs;
668	return 0;
669
670out:
671	kobject_put(&attrs->kobj);
672	return err;
673}
674
675static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
676{
677	struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
678	int err;
679
680	if (!targets)
681		return -ENOMEM;
682	err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
683			&context->kobj, "targets");
684	if (err) {
685		kobject_put(&targets->kobj);
686		return err;
687	}
688	context->targets = targets;
689	return 0;
690}
691
692static int damon_sysfs_context_set_schemes(struct damon_sysfs_context *context)
693{
694	struct damon_sysfs_schemes *schemes = damon_sysfs_schemes_alloc();
695	int err;
696
697	if (!schemes)
698		return -ENOMEM;
699	err = kobject_init_and_add(&schemes->kobj, &damon_sysfs_schemes_ktype,
700			&context->kobj, "schemes");
701	if (err) {
702		kobject_put(&schemes->kobj);
703		return err;
704	}
705	context->schemes = schemes;
706	return 0;
707}
708
709static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
710{
711	int err;
712
713	err = damon_sysfs_context_set_attrs(context);
714	if (err)
715		return err;
716
717	err = damon_sysfs_context_set_targets(context);
718	if (err)
719		goto put_attrs_out;
720
721	err = damon_sysfs_context_set_schemes(context);
722	if (err)
723		goto put_targets_attrs_out;
724	return 0;
725
726put_targets_attrs_out:
727	kobject_put(&context->targets->kobj);
728	context->targets = NULL;
729put_attrs_out:
730	kobject_put(&context->attrs->kobj);
731	context->attrs = NULL;
732	return err;
733}
734
735static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
736{
737	damon_sysfs_attrs_rm_dirs(context->attrs);
738	kobject_put(&context->attrs->kobj);
739	damon_sysfs_targets_rm_dirs(context->targets);
740	kobject_put(&context->targets->kobj);
741	damon_sysfs_schemes_rm_dirs(context->schemes);
742	kobject_put(&context->schemes->kobj);
743}
744
745static ssize_t avail_operations_show(struct kobject *kobj,
746		struct kobj_attribute *attr, char *buf)
747{
748	enum damon_ops_id id;
749	int len = 0;
750
751	for (id = 0; id < NR_DAMON_OPS; id++) {
752		if (!damon_is_registered_ops(id))
753			continue;
754		len += sysfs_emit_at(buf, len, "%s\n",
755				damon_sysfs_ops_strs[id]);
756	}
757	return len;
758}
759
760static ssize_t operations_show(struct kobject *kobj,
761		struct kobj_attribute *attr, char *buf)
762{
763	struct damon_sysfs_context *context = container_of(kobj,
764			struct damon_sysfs_context, kobj);
765
766	return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]);
767}
768
769static ssize_t operations_store(struct kobject *kobj,
770		struct kobj_attribute *attr, const char *buf, size_t count)
771{
772	struct damon_sysfs_context *context = container_of(kobj,
773			struct damon_sysfs_context, kobj);
774	enum damon_ops_id id;
775
776	for (id = 0; id < NR_DAMON_OPS; id++) {
777		if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
778			context->ops_id = id;
779			return count;
780		}
781	}
782	return -EINVAL;
783}
784
785static void damon_sysfs_context_release(struct kobject *kobj)
786{
787	kfree(container_of(kobj, struct damon_sysfs_context, kobj));
788}
789
790static struct kobj_attribute damon_sysfs_context_avail_operations_attr =
791		__ATTR_RO_MODE(avail_operations, 0400);
792
793static struct kobj_attribute damon_sysfs_context_operations_attr =
794		__ATTR_RW_MODE(operations, 0600);
795
796static struct attribute *damon_sysfs_context_attrs[] = {
797	&damon_sysfs_context_avail_operations_attr.attr,
798	&damon_sysfs_context_operations_attr.attr,
799	NULL,
800};
801ATTRIBUTE_GROUPS(damon_sysfs_context);
802
803static const struct kobj_type damon_sysfs_context_ktype = {
804	.release = damon_sysfs_context_release,
805	.sysfs_ops = &kobj_sysfs_ops,
806	.default_groups = damon_sysfs_context_groups,
807};
808
809/*
810 * contexts directory
811 */
812
813struct damon_sysfs_contexts {
814	struct kobject kobj;
815	struct damon_sysfs_context **contexts_arr;
816	int nr;
817};
818
819static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
820{
821	return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL);
822}
823
824static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
825{
826	struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
827	int i;
828
829	for (i = 0; i < contexts->nr; i++) {
830		damon_sysfs_context_rm_dirs(contexts_arr[i]);
831		kobject_put(&contexts_arr[i]->kobj);
832	}
833	contexts->nr = 0;
834	kfree(contexts_arr);
835	contexts->contexts_arr = NULL;
836}
837
838static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
839		int nr_contexts)
840{
841	struct damon_sysfs_context **contexts_arr, *context;
842	int err, i;
843
844	damon_sysfs_contexts_rm_dirs(contexts);
845	if (!nr_contexts)
846		return 0;
847
848	contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr),
849			GFP_KERNEL | __GFP_NOWARN);
850	if (!contexts_arr)
851		return -ENOMEM;
852	contexts->contexts_arr = contexts_arr;
853
854	for (i = 0; i < nr_contexts; i++) {
855		context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
856		if (!context) {
857			damon_sysfs_contexts_rm_dirs(contexts);
858			return -ENOMEM;
859		}
860
861		err = kobject_init_and_add(&context->kobj,
862				&damon_sysfs_context_ktype, &contexts->kobj,
863				"%d", i);
864		if (err)
865			goto out;
866
867		err = damon_sysfs_context_add_dirs(context);
868		if (err)
869			goto out;
870
871		contexts_arr[i] = context;
872		contexts->nr++;
873	}
874	return 0;
875
876out:
877	damon_sysfs_contexts_rm_dirs(contexts);
878	kobject_put(&context->kobj);
879	return err;
880}
881
882static ssize_t nr_contexts_show(struct kobject *kobj,
883		struct kobj_attribute *attr, char *buf)
884{
885	struct damon_sysfs_contexts *contexts = container_of(kobj,
886			struct damon_sysfs_contexts, kobj);
887
888	return sysfs_emit(buf, "%d\n", contexts->nr);
889}
890
891static ssize_t nr_contexts_store(struct kobject *kobj,
892		struct kobj_attribute *attr, const char *buf, size_t count)
893{
894	struct damon_sysfs_contexts *contexts;
895	int nr, err;
896
897	err = kstrtoint(buf, 0, &nr);
898	if (err)
899		return err;
900	/* TODO: support multiple contexts per kdamond */
901	if (nr < 0 || 1 < nr)
902		return -EINVAL;
903
904	contexts = container_of(kobj, struct damon_sysfs_contexts, kobj);
905	if (!mutex_trylock(&damon_sysfs_lock))
906		return -EBUSY;
907	err = damon_sysfs_contexts_add_dirs(contexts, nr);
908	mutex_unlock(&damon_sysfs_lock);
909	if (err)
910		return err;
911
912	return count;
913}
914
915static void damon_sysfs_contexts_release(struct kobject *kobj)
916{
917	kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
918}
919
920static struct kobj_attribute damon_sysfs_contexts_nr_attr
921		= __ATTR_RW_MODE(nr_contexts, 0600);
922
923static struct attribute *damon_sysfs_contexts_attrs[] = {
924	&damon_sysfs_contexts_nr_attr.attr,
925	NULL,
926};
927ATTRIBUTE_GROUPS(damon_sysfs_contexts);
928
929static const struct kobj_type damon_sysfs_contexts_ktype = {
930	.release = damon_sysfs_contexts_release,
931	.sysfs_ops = &kobj_sysfs_ops,
932	.default_groups = damon_sysfs_contexts_groups,
933};
934
935/*
936 * kdamond directory
937 */
938
939struct damon_sysfs_kdamond {
940	struct kobject kobj;
941	struct damon_sysfs_contexts *contexts;
942	struct damon_ctx *damon_ctx;
943};
944
945static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
946{
947	return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL);
948}
949
950static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
951{
952	struct damon_sysfs_contexts *contexts;
953	int err;
954
955	contexts = damon_sysfs_contexts_alloc();
956	if (!contexts)
957		return -ENOMEM;
958
959	err = kobject_init_and_add(&contexts->kobj,
960			&damon_sysfs_contexts_ktype, &kdamond->kobj,
961			"contexts");
962	if (err) {
963		kobject_put(&contexts->kobj);
964		return err;
965	}
966	kdamond->contexts = contexts;
967
968	return err;
969}
970
971static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
972{
973	damon_sysfs_contexts_rm_dirs(kdamond->contexts);
974	kobject_put(&kdamond->contexts->kobj);
975}
976
977static bool damon_sysfs_ctx_running(struct damon_ctx *ctx)
978{
979	bool running;
980
981	mutex_lock(&ctx->kdamond_lock);
982	running = ctx->kdamond != NULL;
983	mutex_unlock(&ctx->kdamond_lock);
984	return running;
985}
986
987/*
988 * enum damon_sysfs_cmd - Commands for a specific kdamond.
989 */
990enum damon_sysfs_cmd {
991	/* @DAMON_SYSFS_CMD_ON: Turn the kdamond on. */
992	DAMON_SYSFS_CMD_ON,
993	/* @DAMON_SYSFS_CMD_OFF: Turn the kdamond off. */
994	DAMON_SYSFS_CMD_OFF,
995	/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
996	DAMON_SYSFS_CMD_COMMIT,
997	/*
998	 * @DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS: Commit the quota goals
999	 * to DAMON.
1000	 */
1001	DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS,
1002	/*
1003	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
1004	 * files.
1005	 */
1006	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
1007	/*
1008	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES: Update
1009	 * tried_regions/total_bytes sysfs files for each scheme.
1010	 */
1011	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES,
1012	/*
1013	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: Update schemes tried
1014	 * regions
1015	 */
1016	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS,
1017	/*
1018	 * @DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS: Clear schemes tried
1019	 * regions
1020	 */
1021	DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS,
1022	/*
1023	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS: Update the
1024	 * effective size quota of the scheme in bytes.
1025	 */
1026	DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS,
1027	/*
1028	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
1029	 */
1030	NR_DAMON_SYSFS_CMDS,
1031};
1032
1033/* Should match with enum damon_sysfs_cmd */
1034static const char * const damon_sysfs_cmd_strs[] = {
1035	"on",
1036	"off",
1037	"commit",
1038	"commit_schemes_quota_goals",
1039	"update_schemes_stats",
1040	"update_schemes_tried_bytes",
1041	"update_schemes_tried_regions",
1042	"clear_schemes_tried_regions",
1043	"update_schemes_effective_quotas",
1044};
1045
1046/*
1047 * struct damon_sysfs_cmd_request - A request to the DAMON callback.
1048 * @cmd:	The command that needs to be handled by the callback.
1049 * @kdamond:	The kobject wrapper that associated to the kdamond thread.
1050 *
1051 * This structure represents a sysfs command request that need to access some
1052 * DAMON context-internal data.  Because DAMON context-internal data can be
1053 * safely accessed from DAMON callbacks without additional synchronization, the
1054 * request will be handled by the DAMON callback.  None-``NULL`` @kdamond means
1055 * the request is valid.
1056 */
1057struct damon_sysfs_cmd_request {
1058	enum damon_sysfs_cmd cmd;
1059	struct damon_sysfs_kdamond *kdamond;
1060};
1061
1062/* Current DAMON callback request.  Protected by damon_sysfs_lock. */
1063static struct damon_sysfs_cmd_request damon_sysfs_cmd_request;
1064
1065static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
1066		char *buf)
1067{
1068	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1069			struct damon_sysfs_kdamond, kobj);
1070	struct damon_ctx *ctx = kdamond->damon_ctx;
1071	bool running;
1072
1073	if (!ctx)
1074		running = false;
1075	else
1076		running = damon_sysfs_ctx_running(ctx);
1077
1078	return sysfs_emit(buf, "%s\n", running ?
1079			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_ON] :
1080			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_OFF]);
1081}
1082
1083static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
1084		struct damon_sysfs_attrs *sys_attrs)
1085{
1086	struct damon_sysfs_intervals *sys_intervals = sys_attrs->intervals;
1087	struct damon_sysfs_ul_range *sys_nr_regions =
1088		sys_attrs->nr_regions_range;
1089	struct damon_attrs attrs = {
1090		.sample_interval = sys_intervals->sample_us,
1091		.aggr_interval = sys_intervals->aggr_us,
1092		.ops_update_interval = sys_intervals->update_us,
1093		.min_nr_regions = sys_nr_regions->min,
1094		.max_nr_regions = sys_nr_regions->max,
1095	};
1096	return damon_set_attrs(ctx, &attrs);
1097}
1098
1099static void damon_sysfs_destroy_targets(struct damon_ctx *ctx)
1100{
1101	struct damon_target *t, *next;
1102	bool has_pid = damon_target_has_pid(ctx);
1103
1104	damon_for_each_target_safe(t, next, ctx) {
1105		if (has_pid)
1106			put_pid(t->pid);
1107		damon_destroy_target(t);
1108	}
1109}
1110
1111static int damon_sysfs_set_regions(struct damon_target *t,
1112		struct damon_sysfs_regions *sysfs_regions)
1113{
1114	struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
1115			sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
1116	int i, err = -EINVAL;
1117
1118	if (!ranges)
1119		return -ENOMEM;
1120	for (i = 0; i < sysfs_regions->nr; i++) {
1121		struct damon_sysfs_region *sys_region =
1122			sysfs_regions->regions_arr[i];
1123
1124		if (sys_region->ar.start > sys_region->ar.end)
1125			goto out;
1126
1127		ranges[i].start = sys_region->ar.start;
1128		ranges[i].end = sys_region->ar.end;
1129		if (i == 0)
1130			continue;
1131		if (ranges[i - 1].end > ranges[i].start)
1132			goto out;
1133	}
1134	err = damon_set_regions(t, ranges, sysfs_regions->nr);
1135out:
1136	kfree(ranges);
1137	return err;
1138
1139}
1140
1141static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
1142		struct damon_ctx *ctx)
1143{
1144	struct damon_target *t = damon_new_target();
1145	int err = -EINVAL;
1146
1147	if (!t)
1148		return -ENOMEM;
1149	damon_add_target(ctx, t);
1150	if (damon_target_has_pid(ctx)) {
1151		t->pid = find_get_pid(sys_target->pid);
1152		if (!t->pid)
1153			goto destroy_targets_out;
1154	}
1155	err = damon_sysfs_set_regions(t, sys_target->regions);
1156	if (err)
1157		goto destroy_targets_out;
1158	return 0;
1159
1160destroy_targets_out:
1161	damon_sysfs_destroy_targets(ctx);
1162	return err;
1163}
1164
1165static int damon_sysfs_update_target_pid(struct damon_target *target, int pid)
1166{
1167	struct pid *pid_new;
1168
1169	pid_new = find_get_pid(pid);
1170	if (!pid_new)
1171		return -EINVAL;
1172
1173	if (pid_new == target->pid) {
1174		put_pid(pid_new);
1175		return 0;
1176	}
1177
1178	put_pid(target->pid);
1179	target->pid = pid_new;
1180	return 0;
1181}
1182
1183static int damon_sysfs_update_target(struct damon_target *target,
1184		struct damon_ctx *ctx,
1185		struct damon_sysfs_target *sys_target)
1186{
1187	int err = 0;
1188
1189	if (damon_target_has_pid(ctx)) {
1190		err = damon_sysfs_update_target_pid(target, sys_target->pid);
1191		if (err)
1192			return err;
1193	}
1194
1195	/*
1196	 * Do monitoring target region boundary update only if one or more
1197	 * regions are set by the user.  This is for keeping current monitoring
1198	 * target results and range easier, especially for dynamic monitoring
1199	 * target regions update ops like 'vaddr'.
1200	 */
1201	if (sys_target->regions->nr)
1202		err = damon_sysfs_set_regions(target, sys_target->regions);
1203	return err;
1204}
1205
1206static int damon_sysfs_set_targets(struct damon_ctx *ctx,
1207		struct damon_sysfs_targets *sysfs_targets)
1208{
1209	struct damon_target *t, *next;
1210	int i = 0, err;
1211
1212	/* Multiple physical address space monitoring targets makes no sense */
1213	if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1)
1214		return -EINVAL;
1215
1216	damon_for_each_target_safe(t, next, ctx) {
1217		if (i < sysfs_targets->nr) {
1218			err = damon_sysfs_update_target(t, ctx,
1219					sysfs_targets->targets_arr[i]);
1220			if (err)
1221				return err;
1222		} else {
1223			if (damon_target_has_pid(ctx))
1224				put_pid(t->pid);
1225			damon_destroy_target(t);
1226		}
1227		i++;
1228	}
1229
1230	for (; i < sysfs_targets->nr; i++) {
1231		struct damon_sysfs_target *st = sysfs_targets->targets_arr[i];
1232
1233		err = damon_sysfs_add_target(st, ctx);
1234		if (err)
1235			return err;
1236	}
1237	return 0;
1238}
1239
1240static bool damon_sysfs_schemes_regions_updating;
1241
1242static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
1243{
1244	struct damon_target *t, *next;
1245	struct damon_sysfs_kdamond *kdamond;
1246	enum damon_sysfs_cmd cmd;
1247
1248	/* damon_sysfs_schemes_update_regions_stop() might not yet called */
1249	kdamond = damon_sysfs_cmd_request.kdamond;
1250	cmd = damon_sysfs_cmd_request.cmd;
1251	if (kdamond && ctx == kdamond->damon_ctx &&
1252			(cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS ||
1253			 cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES) &&
1254			damon_sysfs_schemes_regions_updating) {
1255		damon_sysfs_schemes_update_regions_stop(ctx);
1256		damon_sysfs_schemes_regions_updating = false;
1257		mutex_unlock(&damon_sysfs_lock);
1258	}
1259
1260	if (!damon_target_has_pid(ctx))
1261		return;
1262
1263	mutex_lock(&ctx->kdamond_lock);
1264	damon_for_each_target_safe(t, next, ctx) {
1265		put_pid(t->pid);
1266		damon_destroy_target(t);
1267	}
1268	mutex_unlock(&ctx->kdamond_lock);
1269}
1270
1271/*
1272 * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
1273 * @kdamond:	The kobject wrapper that associated to the kdamond thread.
1274 *
1275 * This function reads the schemes stats of specific kdamond and update the
1276 * related values for sysfs files.  This function should be called from DAMON
1277 * callbacks while holding ``damon_syfs_lock``, to safely access the DAMON
1278 * contexts-internal data and DAMON sysfs variables.
1279 */
1280static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond)
1281{
1282	struct damon_ctx *ctx = kdamond->damon_ctx;
1283
1284	if (!ctx)
1285		return -EINVAL;
1286	damon_sysfs_schemes_update_stats(
1287			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1288	return 0;
1289}
1290
1291static int damon_sysfs_upd_schemes_regions_start(
1292		struct damon_sysfs_kdamond *kdamond, bool total_bytes_only)
1293{
1294	struct damon_ctx *ctx = kdamond->damon_ctx;
1295
1296	if (!ctx)
1297		return -EINVAL;
1298	return damon_sysfs_schemes_update_regions_start(
1299			kdamond->contexts->contexts_arr[0]->schemes, ctx,
1300			total_bytes_only);
1301}
1302
1303static int damon_sysfs_upd_schemes_regions_stop(
1304		struct damon_sysfs_kdamond *kdamond)
1305{
1306	struct damon_ctx *ctx = kdamond->damon_ctx;
1307
1308	if (!ctx)
1309		return -EINVAL;
1310	return damon_sysfs_schemes_update_regions_stop(ctx);
1311}
1312
1313static int damon_sysfs_clear_schemes_regions(
1314		struct damon_sysfs_kdamond *kdamond)
1315{
1316	struct damon_ctx *ctx = kdamond->damon_ctx;
1317
1318	if (!ctx)
1319		return -EINVAL;
1320	return damon_sysfs_schemes_clear_regions(
1321			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1322}
1323
1324static inline bool damon_sysfs_kdamond_running(
1325		struct damon_sysfs_kdamond *kdamond)
1326{
1327	return kdamond->damon_ctx &&
1328		damon_sysfs_ctx_running(kdamond->damon_ctx);
1329}
1330
1331static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
1332		struct damon_sysfs_context *sys_ctx)
1333{
1334	int err;
1335
1336	err = damon_select_ops(ctx, sys_ctx->ops_id);
1337	if (err)
1338		return err;
1339	err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
1340	if (err)
1341		return err;
1342	err = damon_sysfs_set_targets(ctx, sys_ctx->targets);
1343	if (err)
1344		return err;
1345	return damon_sysfs_set_schemes(ctx, sys_ctx->schemes);
1346}
1347
1348/*
1349 * damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
1350 * @kdamond:	The kobject wrapper for the associated kdamond.
1351 *
1352 * If the sysfs input is wrong, the kdamond will be terminated.
1353 */
1354static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
1355{
1356	if (!damon_sysfs_kdamond_running(kdamond))
1357		return -EINVAL;
1358	/* TODO: Support multiple contexts per kdamond */
1359	if (kdamond->contexts->nr != 1)
1360		return -EINVAL;
1361
1362	return damon_sysfs_apply_inputs(kdamond->damon_ctx,
1363			kdamond->contexts->contexts_arr[0]);
1364}
1365
1366static int damon_sysfs_commit_schemes_quota_goals(
1367		struct damon_sysfs_kdamond *sysfs_kdamond)
1368{
1369	struct damon_ctx *ctx;
1370	struct damon_sysfs_context *sysfs_ctx;
1371
1372	if (!damon_sysfs_kdamond_running(sysfs_kdamond))
1373		return -EINVAL;
1374	/* TODO: Support multiple contexts per kdamond */
1375	if (sysfs_kdamond->contexts->nr != 1)
1376		return -EINVAL;
1377
1378	ctx = sysfs_kdamond->damon_ctx;
1379	sysfs_ctx = sysfs_kdamond->contexts->contexts_arr[0];
1380	return damos_sysfs_set_quota_scores(sysfs_ctx->schemes, ctx);
1381}
1382
1383/*
1384 * damon_sysfs_upd_schemes_effective_quotas() - Update schemes effective quotas
1385 * sysfs files.
1386 * @kdamond:	The kobject wrapper that associated to the kdamond thread.
1387 *
1388 * This function reads the schemes' effective quotas of specific kdamond and
1389 * update the related values for sysfs files.  This function should be called
1390 * from DAMON callbacks while holding ``damon_syfs_lock``, to safely access the
1391 * DAMON contexts-internal data and DAMON sysfs variables.
1392 */
1393static int damon_sysfs_upd_schemes_effective_quotas(
1394		struct damon_sysfs_kdamond *kdamond)
1395{
1396	struct damon_ctx *ctx = kdamond->damon_ctx;
1397
1398	if (!ctx)
1399		return -EINVAL;
1400	damos_sysfs_update_effective_quotas(
1401			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1402	return 0;
1403}
1404
1405
1406/*
1407 * damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
1408 * @c:		The DAMON context of the callback.
1409 * @active:	Whether @c is not deactivated due to watermarks.
1410 * @after_aggr:	Whether this is called from after_aggregation() callback.
1411 *
1412 * This function is periodically called back from the kdamond thread for @c.
1413 * Then, it checks if there is a waiting DAMON sysfs request and handles it.
1414 */
1415static int damon_sysfs_cmd_request_callback(struct damon_ctx *c, bool active,
1416		bool after_aggregation)
1417{
1418	struct damon_sysfs_kdamond *kdamond;
1419	bool total_bytes_only = false;
1420	int err = 0;
1421
1422	/* avoid deadlock due to concurrent state_store('off') */
1423	if (!damon_sysfs_schemes_regions_updating &&
1424			!mutex_trylock(&damon_sysfs_lock))
1425		return 0;
1426	kdamond = damon_sysfs_cmd_request.kdamond;
1427	if (!kdamond || kdamond->damon_ctx != c)
1428		goto out;
1429	switch (damon_sysfs_cmd_request.cmd) {
1430	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS:
1431		err = damon_sysfs_upd_schemes_stats(kdamond);
1432		break;
1433	case DAMON_SYSFS_CMD_COMMIT:
1434		if (!after_aggregation)
1435			goto out;
1436		err = damon_sysfs_commit_input(kdamond);
1437		break;
1438	case DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS:
1439		err = damon_sysfs_commit_schemes_quota_goals(kdamond);
1440		break;
1441	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
1442		total_bytes_only = true;
1443		fallthrough;
1444	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:
1445		if (!damon_sysfs_schemes_regions_updating) {
1446			err = damon_sysfs_upd_schemes_regions_start(kdamond,
1447					total_bytes_only);
1448			if (!err) {
1449				damon_sysfs_schemes_regions_updating = true;
1450				goto keep_lock_out;
1451			}
1452		} else {
1453			damos_sysfs_mark_finished_regions_updates(c);
1454			/*
1455			 * Continue regions updating if DAMON is till
1456			 * active and the update for all schemes is not
1457			 * finished.
1458			 */
1459			if (active && !damos_sysfs_regions_upd_done())
1460				goto keep_lock_out;
1461			err = damon_sysfs_upd_schemes_regions_stop(kdamond);
1462			damon_sysfs_schemes_regions_updating = false;
1463		}
1464		break;
1465	case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
1466		err = damon_sysfs_clear_schemes_regions(kdamond);
1467		break;
1468	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS:
1469		err = damon_sysfs_upd_schemes_effective_quotas(kdamond);
1470		break;
1471	default:
1472		break;
1473	}
1474	/* Mark the request as invalid now. */
1475	damon_sysfs_cmd_request.kdamond = NULL;
1476out:
1477	if (!damon_sysfs_schemes_regions_updating)
1478		mutex_unlock(&damon_sysfs_lock);
1479keep_lock_out:
1480	return err;
1481}
1482
1483static int damon_sysfs_after_wmarks_check(struct damon_ctx *c)
1484{
1485	/*
1486	 * after_wmarks_check() is called back while the context is deactivated
1487	 * by watermarks.
1488	 */
1489	return damon_sysfs_cmd_request_callback(c, false, false);
1490}
1491
1492static int damon_sysfs_after_sampling(struct damon_ctx *c)
1493{
1494	/*
1495	 * after_sampling() is called back only while the context is not
1496	 * deactivated by watermarks.
1497	 */
1498	return damon_sysfs_cmd_request_callback(c, true, false);
1499}
1500
1501static int damon_sysfs_after_aggregation(struct damon_ctx *c)
1502{
1503	/*
1504	 * after_aggregation() is called back only while the context is not
1505	 * deactivated by watermarks.
1506	 */
1507	return damon_sysfs_cmd_request_callback(c, true, true);
1508}
1509
1510static struct damon_ctx *damon_sysfs_build_ctx(
1511		struct damon_sysfs_context *sys_ctx)
1512{
1513	struct damon_ctx *ctx = damon_new_ctx();
1514	int err;
1515
1516	if (!ctx)
1517		return ERR_PTR(-ENOMEM);
1518
1519	err = damon_sysfs_apply_inputs(ctx, sys_ctx);
1520	if (err) {
1521		damon_destroy_ctx(ctx);
1522		return ERR_PTR(err);
1523	}
1524
1525	ctx->callback.after_wmarks_check = damon_sysfs_after_wmarks_check;
1526	ctx->callback.after_sampling = damon_sysfs_after_sampling;
1527	ctx->callback.after_aggregation = damon_sysfs_after_aggregation;
1528	ctx->callback.before_terminate = damon_sysfs_before_terminate;
1529	return ctx;
1530}
1531
1532static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond)
1533{
1534	struct damon_ctx *ctx;
1535	int err;
1536
1537	if (damon_sysfs_kdamond_running(kdamond))
1538		return -EBUSY;
1539	if (damon_sysfs_cmd_request.kdamond == kdamond)
1540		return -EBUSY;
1541	/* TODO: support multiple contexts per kdamond */
1542	if (kdamond->contexts->nr != 1)
1543		return -EINVAL;
1544
1545	if (kdamond->damon_ctx)
1546		damon_destroy_ctx(kdamond->damon_ctx);
1547	kdamond->damon_ctx = NULL;
1548
1549	ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
1550	if (IS_ERR(ctx))
1551		return PTR_ERR(ctx);
1552	err = damon_start(&ctx, 1, false);
1553	if (err) {
1554		damon_destroy_ctx(ctx);
1555		return err;
1556	}
1557	kdamond->damon_ctx = ctx;
1558	return err;
1559}
1560
1561static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
1562{
1563	if (!kdamond->damon_ctx)
1564		return -EINVAL;
1565	return damon_stop(&kdamond->damon_ctx, 1);
1566	/*
1567	 * To allow users show final monitoring results of already turned-off
1568	 * DAMON, we free kdamond->damon_ctx in next
1569	 * damon_sysfs_turn_damon_on(), or kdamonds_nr_store()
1570	 */
1571}
1572
1573/*
1574 * damon_sysfs_handle_cmd() - Handle a command for a specific kdamond.
1575 * @cmd:	The command to handle.
1576 * @kdamond:	The kobject wrapper for the associated kdamond.
1577 *
1578 * This function handles a DAMON sysfs command for a kdamond.  For commands
1579 * that need to access running DAMON context-internal data, it requests
1580 * handling of the command to the DAMON callback
1581 * (@damon_sysfs_cmd_request_callback()) and wait until it is properly handled,
1582 * or the context is completed.
1583 *
1584 * Return: 0 on success, negative error code otherwise.
1585 */
1586static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
1587		struct damon_sysfs_kdamond *kdamond)
1588{
1589	bool need_wait = true;
1590
1591	/* Handle commands that doesn't access DAMON context-internal data */
1592	switch (cmd) {
1593	case DAMON_SYSFS_CMD_ON:
1594		return damon_sysfs_turn_damon_on(kdamond);
1595	case DAMON_SYSFS_CMD_OFF:
1596		return damon_sysfs_turn_damon_off(kdamond);
1597	default:
1598		break;
1599	}
1600
1601	/* Pass the command to DAMON callback for safe DAMON context access */
1602	if (damon_sysfs_cmd_request.kdamond)
1603		return -EBUSY;
1604	if (!damon_sysfs_kdamond_running(kdamond))
1605		return -EINVAL;
1606	damon_sysfs_cmd_request.cmd = cmd;
1607	damon_sysfs_cmd_request.kdamond = kdamond;
1608
1609	/*
1610	 * wait until damon_sysfs_cmd_request_callback() handles the request
1611	 * from kdamond context
1612	 */
1613	mutex_unlock(&damon_sysfs_lock);
1614	while (need_wait) {
1615		schedule_timeout_idle(msecs_to_jiffies(100));
1616		if (!mutex_trylock(&damon_sysfs_lock))
1617			continue;
1618		if (!damon_sysfs_cmd_request.kdamond) {
1619			/* damon_sysfs_cmd_request_callback() handled */
1620			need_wait = false;
1621		} else if (!damon_sysfs_kdamond_running(kdamond)) {
1622			/* kdamond has already finished */
1623			need_wait = false;
1624			damon_sysfs_cmd_request.kdamond = NULL;
1625		}
1626		mutex_unlock(&damon_sysfs_lock);
1627	}
1628	mutex_lock(&damon_sysfs_lock);
1629	return 0;
1630}
1631
1632static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
1633		const char *buf, size_t count)
1634{
1635	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1636			struct damon_sysfs_kdamond, kobj);
1637	enum damon_sysfs_cmd cmd;
1638	ssize_t ret = -EINVAL;
1639
1640	if (!mutex_trylock(&damon_sysfs_lock))
1641		return -EBUSY;
1642	for (cmd = 0; cmd < NR_DAMON_SYSFS_CMDS; cmd++) {
1643		if (sysfs_streq(buf, damon_sysfs_cmd_strs[cmd])) {
1644			ret = damon_sysfs_handle_cmd(cmd, kdamond);
1645			break;
1646		}
1647	}
1648	mutex_unlock(&damon_sysfs_lock);
1649	if (!ret)
1650		ret = count;
1651	return ret;
1652}
1653
1654static ssize_t pid_show(struct kobject *kobj,
1655		struct kobj_attribute *attr, char *buf)
1656{
1657	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1658			struct damon_sysfs_kdamond, kobj);
1659	struct damon_ctx *ctx;
1660	int pid = -1;
1661
1662	if (!mutex_trylock(&damon_sysfs_lock))
1663		return -EBUSY;
1664	ctx = kdamond->damon_ctx;
1665	if (!ctx)
1666		goto out;
1667
1668	mutex_lock(&ctx->kdamond_lock);
1669	if (ctx->kdamond)
1670		pid = ctx->kdamond->pid;
1671	mutex_unlock(&ctx->kdamond_lock);
1672out:
1673	mutex_unlock(&damon_sysfs_lock);
1674	return sysfs_emit(buf, "%d\n", pid);
1675}
1676
1677static void damon_sysfs_kdamond_release(struct kobject *kobj)
1678{
1679	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1680			struct damon_sysfs_kdamond, kobj);
1681
1682	if (kdamond->damon_ctx)
1683		damon_destroy_ctx(kdamond->damon_ctx);
1684	kfree(kdamond);
1685}
1686
1687static struct kobj_attribute damon_sysfs_kdamond_state_attr =
1688		__ATTR_RW_MODE(state, 0600);
1689
1690static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
1691		__ATTR_RO_MODE(pid, 0400);
1692
1693static struct attribute *damon_sysfs_kdamond_attrs[] = {
1694	&damon_sysfs_kdamond_state_attr.attr,
1695	&damon_sysfs_kdamond_pid_attr.attr,
1696	NULL,
1697};
1698ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
1699
1700static const struct kobj_type damon_sysfs_kdamond_ktype = {
1701	.release = damon_sysfs_kdamond_release,
1702	.sysfs_ops = &kobj_sysfs_ops,
1703	.default_groups = damon_sysfs_kdamond_groups,
1704};
1705
1706/*
1707 * kdamonds directory
1708 */
1709
1710struct damon_sysfs_kdamonds {
1711	struct kobject kobj;
1712	struct damon_sysfs_kdamond **kdamonds_arr;
1713	int nr;
1714};
1715
1716static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
1717{
1718	return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL);
1719}
1720
1721static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
1722{
1723	struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
1724	int i;
1725
1726	for (i = 0; i < kdamonds->nr; i++) {
1727		damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
1728		kobject_put(&kdamonds_arr[i]->kobj);
1729	}
1730	kdamonds->nr = 0;
1731	kfree(kdamonds_arr);
1732	kdamonds->kdamonds_arr = NULL;
1733}
1734
1735static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
1736		int nr_kdamonds)
1737{
1738	int i;
1739
1740	for (i = 0; i < nr_kdamonds; i++) {
1741		if (damon_sysfs_kdamond_running(kdamonds[i]) ||
1742		    damon_sysfs_cmd_request.kdamond == kdamonds[i])
1743			return true;
1744	}
1745
1746	return false;
1747}
1748
1749static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
1750		int nr_kdamonds)
1751{
1752	struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
1753	int err, i;
1754
1755	if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
1756		return -EBUSY;
1757
1758	damon_sysfs_kdamonds_rm_dirs(kdamonds);
1759	if (!nr_kdamonds)
1760		return 0;
1761
1762	kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr),
1763			GFP_KERNEL | __GFP_NOWARN);
1764	if (!kdamonds_arr)
1765		return -ENOMEM;
1766	kdamonds->kdamonds_arr = kdamonds_arr;
1767
1768	for (i = 0; i < nr_kdamonds; i++) {
1769		kdamond = damon_sysfs_kdamond_alloc();
1770		if (!kdamond) {
1771			damon_sysfs_kdamonds_rm_dirs(kdamonds);
1772			return -ENOMEM;
1773		}
1774
1775		err = kobject_init_and_add(&kdamond->kobj,
1776				&damon_sysfs_kdamond_ktype, &kdamonds->kobj,
1777				"%d", i);
1778		if (err)
1779			goto out;
1780
1781		err = damon_sysfs_kdamond_add_dirs(kdamond);
1782		if (err)
1783			goto out;
1784
1785		kdamonds_arr[i] = kdamond;
1786		kdamonds->nr++;
1787	}
1788	return 0;
1789
1790out:
1791	damon_sysfs_kdamonds_rm_dirs(kdamonds);
1792	kobject_put(&kdamond->kobj);
1793	return err;
1794}
1795
1796static ssize_t nr_kdamonds_show(struct kobject *kobj,
1797		struct kobj_attribute *attr, char *buf)
1798{
1799	struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
1800			struct damon_sysfs_kdamonds, kobj);
1801
1802	return sysfs_emit(buf, "%d\n", kdamonds->nr);
1803}
1804
1805static ssize_t nr_kdamonds_store(struct kobject *kobj,
1806		struct kobj_attribute *attr, const char *buf, size_t count)
1807{
1808	struct damon_sysfs_kdamonds *kdamonds;
1809	int nr, err;
1810
1811	err = kstrtoint(buf, 0, &nr);
1812	if (err)
1813		return err;
1814	if (nr < 0)
1815		return -EINVAL;
1816
1817	kdamonds = container_of(kobj, struct damon_sysfs_kdamonds, kobj);
1818
1819	if (!mutex_trylock(&damon_sysfs_lock))
1820		return -EBUSY;
1821	err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
1822	mutex_unlock(&damon_sysfs_lock);
1823	if (err)
1824		return err;
1825
1826	return count;
1827}
1828
1829static void damon_sysfs_kdamonds_release(struct kobject *kobj)
1830{
1831	kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
1832}
1833
1834static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
1835		__ATTR_RW_MODE(nr_kdamonds, 0600);
1836
1837static struct attribute *damon_sysfs_kdamonds_attrs[] = {
1838	&damon_sysfs_kdamonds_nr_attr.attr,
1839	NULL,
1840};
1841ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
1842
1843static const struct kobj_type damon_sysfs_kdamonds_ktype = {
1844	.release = damon_sysfs_kdamonds_release,
1845	.sysfs_ops = &kobj_sysfs_ops,
1846	.default_groups = damon_sysfs_kdamonds_groups,
1847};
1848
1849/*
1850 * damon user interface directory
1851 */
1852
1853struct damon_sysfs_ui_dir {
1854	struct kobject kobj;
1855	struct damon_sysfs_kdamonds *kdamonds;
1856};
1857
1858static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
1859{
1860	return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL);
1861}
1862
1863static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
1864{
1865	struct damon_sysfs_kdamonds *kdamonds;
1866	int err;
1867
1868	kdamonds = damon_sysfs_kdamonds_alloc();
1869	if (!kdamonds)
1870		return -ENOMEM;
1871
1872	err = kobject_init_and_add(&kdamonds->kobj,
1873			&damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
1874			"kdamonds");
1875	if (err) {
1876		kobject_put(&kdamonds->kobj);
1877		return err;
1878	}
1879	ui_dir->kdamonds = kdamonds;
1880	return err;
1881}
1882
1883static void damon_sysfs_ui_dir_release(struct kobject *kobj)
1884{
1885	kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
1886}
1887
1888static struct attribute *damon_sysfs_ui_dir_attrs[] = {
1889	NULL,
1890};
1891ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
1892
1893static const struct kobj_type damon_sysfs_ui_dir_ktype = {
1894	.release = damon_sysfs_ui_dir_release,
1895	.sysfs_ops = &kobj_sysfs_ops,
1896	.default_groups = damon_sysfs_ui_dir_groups,
1897};
1898
1899static int __init damon_sysfs_init(void)
1900{
1901	struct kobject *damon_sysfs_root;
1902	struct damon_sysfs_ui_dir *admin;
1903	int err;
1904
1905	damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
1906	if (!damon_sysfs_root)
1907		return -ENOMEM;
1908
1909	admin = damon_sysfs_ui_dir_alloc();
1910	if (!admin) {
1911		kobject_put(damon_sysfs_root);
1912		return -ENOMEM;
1913	}
1914	err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
1915			damon_sysfs_root, "admin");
1916	if (err)
1917		goto out;
1918	err = damon_sysfs_ui_dir_add_dirs(admin);
1919	if (err)
1920		goto out;
1921	return 0;
1922
1923out:
1924	kobject_put(&admin->kobj);
1925	kobject_put(damon_sysfs_root);
1926	return err;
1927}
1928subsys_initcall(damon_sysfs_init);
1929
1930#include "sysfs-test.h"
1931