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
 18static 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
 26static 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
 34static 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	if (hctx->flags & BLK_MQ_F_BLOCKING)
 40		cleanup_srcu_struct(hctx->srcu);
 41	blk_free_flush_queue(hctx->fq);
 42	sbitmap_free(&hctx->ctx_map);
 43	free_cpumask_var(hctx->cpumask);
 44	kfree(hctx->ctxs);
 45	kfree(hctx);
 46}
 47
 48struct blk_mq_ctx_sysfs_entry {
 49	struct attribute attr;
 50	ssize_t (*show)(struct blk_mq_ctx *, char *);
 51	ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
 52};
 53
 54struct blk_mq_hw_ctx_sysfs_entry {
 55	struct attribute attr;
 56	ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
 57	ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
 58};
 59
 60static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
 61				 char *page)
 62{
 63	struct blk_mq_ctx_sysfs_entry *entry;
 64	struct blk_mq_ctx *ctx;
 65	struct request_queue *q;
 66	ssize_t res;
 67
 68	entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
 69	ctx = container_of(kobj, struct blk_mq_ctx, kobj);
 70	q = ctx->queue;
 71
 72	if (!entry->show)
 73		return -EIO;
 74
 75	mutex_lock(&q->sysfs_lock);
 76	res = entry->show(ctx, page);
 77	mutex_unlock(&q->sysfs_lock);
 78	return res;
 79}
 80
 81static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
 82				  const char *page, size_t length)
 83{
 84	struct blk_mq_ctx_sysfs_entry *entry;
 85	struct blk_mq_ctx *ctx;
 86	struct request_queue *q;
 87	ssize_t res;
 88
 89	entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
 90	ctx = container_of(kobj, struct blk_mq_ctx, kobj);
 91	q = ctx->queue;
 92
 93	if (!entry->store)
 94		return -EIO;
 95
 96	mutex_lock(&q->sysfs_lock);
 97	res = entry->store(ctx, page, length);
 98	mutex_unlock(&q->sysfs_lock);
 99	return res;
100}
101
102static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
103				    struct attribute *attr, char *page)
104{
105	struct blk_mq_hw_ctx_sysfs_entry *entry;
106	struct blk_mq_hw_ctx *hctx;
107	struct request_queue *q;
108	ssize_t res;
109
110	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
111	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
112	q = hctx->queue;
113
114	if (!entry->show)
115		return -EIO;
116
117	mutex_lock(&q->sysfs_lock);
118	res = entry->show(hctx, page);
119	mutex_unlock(&q->sysfs_lock);
120	return res;
121}
122
123static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
124				     struct attribute *attr, const char *page,
125				     size_t length)
126{
127	struct blk_mq_hw_ctx_sysfs_entry *entry;
128	struct blk_mq_hw_ctx *hctx;
129	struct request_queue *q;
130	ssize_t res;
131
132	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
133	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
134	q = hctx->queue;
135
136	if (!entry->store)
137		return -EIO;
138
139	mutex_lock(&q->sysfs_lock);
140	res = entry->store(hctx, page, length);
141	mutex_unlock(&q->sysfs_lock);
142	return res;
143}
144
145static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
146					    char *page)
147{
148	return sprintf(page, "%u\n", hctx->tags->nr_tags);
149}
150
151static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
152						     char *page)
153{
154	return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
155}
156
157static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
158{
159	const size_t size = PAGE_SIZE - 1;
160	unsigned int i, first = 1;
161	int ret = 0, pos = 0;
162
163	for_each_cpu(i, hctx->cpumask) {
164		if (first)
165			ret = snprintf(pos + page, size - pos, "%u", i);
166		else
167			ret = snprintf(pos + page, size - pos, ", %u", i);
168
169		if (ret >= size - pos)
170			break;
171
172		first = 0;
173		pos += ret;
174	}
175
176	ret = snprintf(pos + page, size + 1 - pos, "\n");
177	return pos + ret;
178}
179
180static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
181	.attr = {.name = "nr_tags", .mode = 0444 },
182	.show = blk_mq_hw_sysfs_nr_tags_show,
183};
184static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
185	.attr = {.name = "nr_reserved_tags", .mode = 0444 },
186	.show = blk_mq_hw_sysfs_nr_reserved_tags_show,
187};
188static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
189	.attr = {.name = "cpu_list", .mode = 0444 },
190	.show = blk_mq_hw_sysfs_cpus_show,
191};
192
193static struct attribute *default_hw_ctx_attrs[] = {
194	&blk_mq_hw_sysfs_nr_tags.attr,
195	&blk_mq_hw_sysfs_nr_reserved_tags.attr,
196	&blk_mq_hw_sysfs_cpus.attr,
197	NULL,
198};
199ATTRIBUTE_GROUPS(default_hw_ctx);
200
201static const struct sysfs_ops blk_mq_sysfs_ops = {
202	.show	= blk_mq_sysfs_show,
203	.store	= blk_mq_sysfs_store,
204};
205
206static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
207	.show	= blk_mq_hw_sysfs_show,
208	.store	= blk_mq_hw_sysfs_store,
209};
210
211static struct kobj_type blk_mq_ktype = {
212	.sysfs_ops	= &blk_mq_sysfs_ops,
213	.release	= blk_mq_sysfs_release,
214};
215
216static struct kobj_type blk_mq_ctx_ktype = {
217	.sysfs_ops	= &blk_mq_sysfs_ops,
218	.release	= blk_mq_ctx_sysfs_release,
219};
220
221static struct kobj_type blk_mq_hw_ktype = {
222	.sysfs_ops	= &blk_mq_hw_sysfs_ops,
223	.default_groups = default_hw_ctx_groups,
224	.release	= blk_mq_hw_sysfs_release,
225};
226
227static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
228{
229	struct blk_mq_ctx *ctx;
230	int i;
231
232	if (!hctx->nr_ctx)
233		return;
234
235	hctx_for_each_ctx(hctx, ctx, i)
236		kobject_del(&ctx->kobj);
237
238	kobject_del(&hctx->kobj);
239}
240
241static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
242{
243	struct request_queue *q = hctx->queue;
244	struct blk_mq_ctx *ctx;
245	int i, ret;
246
247	if (!hctx->nr_ctx)
248		return 0;
249
250	ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
251	if (ret)
252		return ret;
253
254	hctx_for_each_ctx(hctx, ctx, i) {
255		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
256		if (ret)
257			break;
258	}
259
260	return ret;
261}
262
263void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
264{
265	struct blk_mq_hw_ctx *hctx;
266	int i;
267
268	lockdep_assert_held(&q->sysfs_dir_lock);
269
270	queue_for_each_hw_ctx(q, hctx, i)
271		blk_mq_unregister_hctx(hctx);
272
273	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
274	kobject_del(q->mq_kobj);
275	kobject_put(&dev->kobj);
276
277	q->mq_sysfs_init_done = false;
278}
279
280void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
281{
282	kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
283}
284
285void blk_mq_sysfs_deinit(struct request_queue *q)
286{
287	struct blk_mq_ctx *ctx;
288	int cpu;
289
290	for_each_possible_cpu(cpu) {
291		ctx = per_cpu_ptr(q->queue_ctx, cpu);
292		kobject_put(&ctx->kobj);
293	}
294	kobject_put(q->mq_kobj);
295}
296
297void blk_mq_sysfs_init(struct request_queue *q)
298{
299	struct blk_mq_ctx *ctx;
300	int cpu;
301
302	kobject_init(q->mq_kobj, &blk_mq_ktype);
303
304	for_each_possible_cpu(cpu) {
305		ctx = per_cpu_ptr(q->queue_ctx, cpu);
306
307		kobject_get(q->mq_kobj);
308		kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
309	}
310}
311
312int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
313{
314	struct blk_mq_hw_ctx *hctx;
315	int ret, i;
316
317	WARN_ON_ONCE(!q->kobj.parent);
318	lockdep_assert_held(&q->sysfs_dir_lock);
319
320	ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
321	if (ret < 0)
322		goto out;
323
324	kobject_uevent(q->mq_kobj, KOBJ_ADD);
325
326	queue_for_each_hw_ctx(q, hctx, i) {
327		ret = blk_mq_register_hctx(hctx);
328		if (ret)
329			goto unreg;
330	}
331
332	q->mq_sysfs_init_done = true;
333
334out:
335	return ret;
336
337unreg:
338	while (--i >= 0)
339		blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
340
341	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
342	kobject_del(q->mq_kobj);
343	kobject_put(&dev->kobj);
344	return ret;
345}
346
347void blk_mq_sysfs_unregister(struct request_queue *q)
348{
349	struct blk_mq_hw_ctx *hctx;
350	int i;
351
352	mutex_lock(&q->sysfs_dir_lock);
353	if (!q->mq_sysfs_init_done)
354		goto unlock;
355
356	queue_for_each_hw_ctx(q, hctx, i)
357		blk_mq_unregister_hctx(hctx);
358
359unlock:
360	mutex_unlock(&q->sysfs_dir_lock);
361}
362
363int blk_mq_sysfs_register(struct request_queue *q)
364{
365	struct blk_mq_hw_ctx *hctx;
366	int i, ret = 0;
367
368	mutex_lock(&q->sysfs_dir_lock);
369	if (!q->mq_sysfs_init_done)
370		goto unlock;
371
372	queue_for_each_hw_ctx(q, hctx, i) {
373		ret = blk_mq_register_hctx(hctx);
374		if (ret)
375			break;
376	}
377
378unlock:
379	mutex_unlock(&q->sysfs_dir_lock);
380
381	return ret;
382}