xref: /openbmc/linux/block/blk-mq-sysfs.c (revision 8795a739) 
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/module.h>
4 #include <linux/backing-dev.h>
5 #include <linux/bio.h>
6 #include <linux/blkdev.h>
7 #include <linux/mm.h>
8 #include <linux/init.h>
9 #include <linux/slab.h>
10 #include <linux/workqueue.h>
11 #include <linux/smp.h>
12 
13 #include <linux/blk-mq.h>
14 #include "blk.h"
15 #include "blk-mq.h"
16 #include "blk-mq-tag.h"
17 
18 static void blk_mq_sysfs_release(struct kobject *kobj)
19 {
20 	struct blk_mq_ctxs *ctxs = container_of(kobj, struct blk_mq_ctxs, kobj);
21 
22 	free_percpu(ctxs->queue_ctx);
23 	kfree(ctxs);
24 }
25 
26 static void blk_mq_ctx_sysfs_release(struct kobject *kobj)
27 {
28 	struct blk_mq_ctx *ctx = container_of(kobj, struct blk_mq_ctx, kobj);
29 
30 	/* ctx->ctxs won't be released until all ctx are freed */
31 	kobject_put(&ctx->ctxs->kobj);
32 }
33 
34 static void blk_mq_hw_sysfs_release(struct kobject *kobj)
35 {
36 	struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
37 						  kobj);
38 
39 	cancel_delayed_work_sync(&hctx->run_work);
40 
41 	if (hctx->flags & BLK_MQ_F_BLOCKING)
42 		cleanup_srcu_struct(hctx->srcu);
43 	blk_free_flush_queue(hctx->fq);
44 	sbitmap_free(&hctx->ctx_map);
45 	free_cpumask_var(hctx->cpumask);
46 	kfree(hctx->ctxs);
47 	kfree(hctx);
48 }
49 
50 struct blk_mq_ctx_sysfs_entry {
51 	struct attribute attr;
52 	ssize_t (*show)(struct blk_mq_ctx *, char *);
53 	ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
54 };
55 
56 struct blk_mq_hw_ctx_sysfs_entry {
57 	struct attribute attr;
58 	ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
59 	ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
60 };
61 
62 static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
63 				 char *page)
64 {
65 	struct blk_mq_ctx_sysfs_entry *entry;
66 	struct blk_mq_ctx *ctx;
67 	struct request_queue *q;
68 	ssize_t res;
69 
70 	entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
71 	ctx = container_of(kobj, struct blk_mq_ctx, kobj);
72 	q = ctx->queue;
73 
74 	if (!entry->show)
75 		return -EIO;
76 
77 	res = -ENOENT;
78 	mutex_lock(&q->sysfs_lock);
79 	if (!blk_queue_dying(q))
80 		res = entry->show(ctx, page);
81 	mutex_unlock(&q->sysfs_lock);
82 	return res;
83 }
84 
85 static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
86 				  const char *page, size_t length)
87 {
88 	struct blk_mq_ctx_sysfs_entry *entry;
89 	struct blk_mq_ctx *ctx;
90 	struct request_queue *q;
91 	ssize_t res;
92 
93 	entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
94 	ctx = container_of(kobj, struct blk_mq_ctx, kobj);
95 	q = ctx->queue;
96 
97 	if (!entry->store)
98 		return -EIO;
99 
100 	res = -ENOENT;
101 	mutex_lock(&q->sysfs_lock);
102 	if (!blk_queue_dying(q))
103 		res = entry->store(ctx, page, length);
104 	mutex_unlock(&q->sysfs_lock);
105 	return res;
106 }
107 
108 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
109 				    struct attribute *attr, char *page)
110 {
111 	struct blk_mq_hw_ctx_sysfs_entry *entry;
112 	struct blk_mq_hw_ctx *hctx;
113 	struct request_queue *q;
114 	ssize_t res;
115 
116 	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
117 	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
118 	q = hctx->queue;
119 
120 	if (!entry->show)
121 		return -EIO;
122 
123 	res = -ENOENT;
124 	mutex_lock(&q->sysfs_lock);
125 	if (!blk_queue_dying(q))
126 		res = entry->show(hctx, page);
127 	mutex_unlock(&q->sysfs_lock);
128 	return res;
129 }
130 
131 static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
132 				     struct attribute *attr, const char *page,
133 				     size_t length)
134 {
135 	struct blk_mq_hw_ctx_sysfs_entry *entry;
136 	struct blk_mq_hw_ctx *hctx;
137 	struct request_queue *q;
138 	ssize_t res;
139 
140 	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
141 	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
142 	q = hctx->queue;
143 
144 	if (!entry->store)
145 		return -EIO;
146 
147 	res = -ENOENT;
148 	mutex_lock(&q->sysfs_lock);
149 	if (!blk_queue_dying(q))
150 		res = entry->store(hctx, page, length);
151 	mutex_unlock(&q->sysfs_lock);
152 	return res;
153 }
154 
155 static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
156 					    char *page)
157 {
158 	return sprintf(page, "%u\n", hctx->tags->nr_tags);
159 }
160 
161 static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
162 						     char *page)
163 {
164 	return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
165 }
166 
167 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
168 {
169 	unsigned int i, first = 1;
170 	ssize_t ret = 0;
171 
172 	for_each_cpu(i, hctx->cpumask) {
173 		if (first)
174 			ret += sprintf(ret + page, "%u", i);
175 		else
176 			ret += sprintf(ret + page, ", %u", i);
177 
178 		first = 0;
179 	}
180 
181 	ret += sprintf(ret + page, "\n");
182 	return ret;
183 }
184 
185 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
186 	.attr = {.name = "nr_tags", .mode = 0444 },
187 	.show = blk_mq_hw_sysfs_nr_tags_show,
188 };
189 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
190 	.attr = {.name = "nr_reserved_tags", .mode = 0444 },
191 	.show = blk_mq_hw_sysfs_nr_reserved_tags_show,
192 };
193 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
194 	.attr = {.name = "cpu_list", .mode = 0444 },
195 	.show = blk_mq_hw_sysfs_cpus_show,
196 };
197 
198 static struct attribute *default_hw_ctx_attrs[] = {
199 	&blk_mq_hw_sysfs_nr_tags.attr,
200 	&blk_mq_hw_sysfs_nr_reserved_tags.attr,
201 	&blk_mq_hw_sysfs_cpus.attr,
202 	NULL,
203 };
204 ATTRIBUTE_GROUPS(default_hw_ctx);
205 
206 static const struct sysfs_ops blk_mq_sysfs_ops = {
207 	.show	= blk_mq_sysfs_show,
208 	.store	= blk_mq_sysfs_store,
209 };
210 
211 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
212 	.show	= blk_mq_hw_sysfs_show,
213 	.store	= blk_mq_hw_sysfs_store,
214 };
215 
216 static struct kobj_type blk_mq_ktype = {
217 	.sysfs_ops	= &blk_mq_sysfs_ops,
218 	.release	= blk_mq_sysfs_release,
219 };
220 
221 static struct kobj_type blk_mq_ctx_ktype = {
222 	.sysfs_ops	= &blk_mq_sysfs_ops,
223 	.release	= blk_mq_ctx_sysfs_release,
224 };
225 
226 static struct kobj_type blk_mq_hw_ktype = {
227 	.sysfs_ops	= &blk_mq_hw_sysfs_ops,
228 	.default_groups = default_hw_ctx_groups,
229 	.release	= blk_mq_hw_sysfs_release,
230 };
231 
232 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
233 {
234 	struct blk_mq_ctx *ctx;
235 	int i;
236 
237 	if (!hctx->nr_ctx)
238 		return;
239 
240 	hctx_for_each_ctx(hctx, ctx, i)
241 		kobject_del(&ctx->kobj);
242 
243 	kobject_del(&hctx->kobj);
244 }
245 
246 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
247 {
248 	struct request_queue *q = hctx->queue;
249 	struct blk_mq_ctx *ctx;
250 	int i, ret;
251 
252 	if (!hctx->nr_ctx)
253 		return 0;
254 
255 	ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
256 	if (ret)
257 		return ret;
258 
259 	hctx_for_each_ctx(hctx, ctx, i) {
260 		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
261 		if (ret)
262 			break;
263 	}
264 
265 	return ret;
266 }
267 
268 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
269 {
270 	struct blk_mq_hw_ctx *hctx;
271 	int i;
272 
273 	lockdep_assert_held(&q->sysfs_dir_lock);
274 
275 	queue_for_each_hw_ctx(q, hctx, i)
276 		blk_mq_unregister_hctx(hctx);
277 
278 	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
279 	kobject_del(q->mq_kobj);
280 	kobject_put(&dev->kobj);
281 
282 	q->mq_sysfs_init_done = false;
283 }
284 
285 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
286 {
287 	kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
288 }
289 
290 void blk_mq_sysfs_deinit(struct request_queue *q)
291 {
292 	struct blk_mq_ctx *ctx;
293 	int cpu;
294 
295 	for_each_possible_cpu(cpu) {
296 		ctx = per_cpu_ptr(q->queue_ctx, cpu);
297 		kobject_put(&ctx->kobj);
298 	}
299 	kobject_put(q->mq_kobj);
300 }
301 
302 void blk_mq_sysfs_init(struct request_queue *q)
303 {
304 	struct blk_mq_ctx *ctx;
305 	int cpu;
306 
307 	kobject_init(q->mq_kobj, &blk_mq_ktype);
308 
309 	for_each_possible_cpu(cpu) {
310 		ctx = per_cpu_ptr(q->queue_ctx, cpu);
311 
312 		kobject_get(q->mq_kobj);
313 		kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
314 	}
315 }
316 
317 int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
318 {
319 	struct blk_mq_hw_ctx *hctx;
320 	int ret, i;
321 
322 	WARN_ON_ONCE(!q->kobj.parent);
323 	lockdep_assert_held(&q->sysfs_dir_lock);
324 
325 	ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
326 	if (ret < 0)
327 		goto out;
328 
329 	kobject_uevent(q->mq_kobj, KOBJ_ADD);
330 
331 	queue_for_each_hw_ctx(q, hctx, i) {
332 		ret = blk_mq_register_hctx(hctx);
333 		if (ret)
334 			goto unreg;
335 	}
336 
337 	q->mq_sysfs_init_done = true;
338 
339 out:
340 	return ret;
341 
342 unreg:
343 	while (--i >= 0)
344 		blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
345 
346 	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
347 	kobject_del(q->mq_kobj);
348 	kobject_put(&dev->kobj);
349 	return ret;
350 }
351 
352 void blk_mq_sysfs_unregister(struct request_queue *q)
353 {
354 	struct blk_mq_hw_ctx *hctx;
355 	int i;
356 
357 	mutex_lock(&q->sysfs_dir_lock);
358 	if (!q->mq_sysfs_init_done)
359 		goto unlock;
360 
361 	queue_for_each_hw_ctx(q, hctx, i)
362 		blk_mq_unregister_hctx(hctx);
363 
364 unlock:
365 	mutex_unlock(&q->sysfs_dir_lock);
366 }
367 
368 int blk_mq_sysfs_register(struct request_queue *q)
369 {
370 	struct blk_mq_hw_ctx *hctx;
371 	int i, ret = 0;
372 
373 	mutex_lock(&q->sysfs_dir_lock);
374 	if (!q->mq_sysfs_init_done)
375 		goto unlock;
376 
377 	queue_for_each_hw_ctx(q, hctx, i) {
378 		ret = blk_mq_register_hctx(hctx);
379 		if (ret)
380 			break;
381 	}
382 
383 unlock:
384 	mutex_unlock(&q->sysfs_dir_lock);
385 
386 	return ret;
387 }
388