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 "blk.h"
 14#include "blk-mq.h"
 15
 16static void blk_mq_sysfs_release(struct kobject *kobj)
 17{
 18	struct blk_mq_ctxs *ctxs = container_of(kobj, struct blk_mq_ctxs, kobj);
 19
 20	free_percpu(ctxs->queue_ctx);
 21	kfree(ctxs);
 22}
 23
 24static void blk_mq_ctx_sysfs_release(struct kobject *kobj)
 25{
 26	struct blk_mq_ctx *ctx = container_of(kobj, struct blk_mq_ctx, kobj);
 27
 28	/* ctx->ctxs won't be released until all ctx are freed */
 29	kobject_put(&ctx->ctxs->kobj);
 30}
 31
 32static void blk_mq_hw_sysfs_release(struct kobject *kobj)
 33{
 34	struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
 35						  kobj);
 36
 37	blk_free_flush_queue(hctx->fq);
 38	sbitmap_free(&hctx->ctx_map);
 39	free_cpumask_var(hctx->cpumask);
 40	kfree(hctx->ctxs);
 41	kfree(hctx);
 42}
 43
 44struct blk_mq_hw_ctx_sysfs_entry {
 45	struct attribute attr;
 46	ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
 47};
 48
 49static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
 50				    struct attribute *attr, char *page)
 51{
 52	struct blk_mq_hw_ctx_sysfs_entry *entry;
 53	struct blk_mq_hw_ctx *hctx;
 54	struct request_queue *q;
 55	ssize_t res;
 56
 57	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
 58	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
 59	q = hctx->queue;
 60
 61	if (!entry->show)
 62		return -EIO;
 63
 64	mutex_lock(&q->sysfs_lock);
 65	res = entry->show(hctx, page);
 66	mutex_unlock(&q->sysfs_lock);
 67	return res;
 68}
 69
 70static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
 71					    char *page)
 72{
 73	return sprintf(page, "%u\n", hctx->tags->nr_tags);
 74}
 75
 76static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
 77						     char *page)
 78{
 79	return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
 80}
 81
 82static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 83{
 84	const size_t size = PAGE_SIZE - 1;
 85	unsigned int i, first = 1;
 86	int ret = 0, pos = 0;
 87
 88	for_each_cpu(i, hctx->cpumask) {
 89		if (first)
 90			ret = snprintf(pos + page, size - pos, "%u", i);
 91		else
 92			ret = snprintf(pos + page, size - pos, ", %u", i);
 93
 94		if (ret >= size - pos)
 95			break;
 96
 97		first = 0;
 98		pos += ret;
 99	}
100
101	ret = snprintf(pos + page, size + 1 - pos, "\n");
102	return pos + ret;
103}
104
105static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
106	.attr = {.name = "nr_tags", .mode = 0444 },
107	.show = blk_mq_hw_sysfs_nr_tags_show,
108};
109static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
110	.attr = {.name = "nr_reserved_tags", .mode = 0444 },
111	.show = blk_mq_hw_sysfs_nr_reserved_tags_show,
112};
113static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
114	.attr = {.name = "cpu_list", .mode = 0444 },
115	.show = blk_mq_hw_sysfs_cpus_show,
116};
117
118static struct attribute *default_hw_ctx_attrs[] = {
119	&blk_mq_hw_sysfs_nr_tags.attr,
120	&blk_mq_hw_sysfs_nr_reserved_tags.attr,
121	&blk_mq_hw_sysfs_cpus.attr,
122	NULL,
123};
124ATTRIBUTE_GROUPS(default_hw_ctx);
125
126static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
127	.show	= blk_mq_hw_sysfs_show,
128};
129
130static const struct kobj_type blk_mq_ktype = {
131	.release	= blk_mq_sysfs_release,
132};
133
134static const struct kobj_type blk_mq_ctx_ktype = {
135	.release	= blk_mq_ctx_sysfs_release,
136};
137
138static const struct kobj_type blk_mq_hw_ktype = {
139	.sysfs_ops	= &blk_mq_hw_sysfs_ops,
140	.default_groups = default_hw_ctx_groups,
141	.release	= blk_mq_hw_sysfs_release,
142};
143
144static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
145{
146	struct blk_mq_ctx *ctx;
147	int i;
148
149	if (!hctx->nr_ctx)
150		return;
151
152	hctx_for_each_ctx(hctx, ctx, i)
153		kobject_del(&ctx->kobj);
154
155	kobject_del(&hctx->kobj);
156}
157
158static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
159{
160	struct request_queue *q = hctx->queue;
161	struct blk_mq_ctx *ctx;
162	int i, j, ret;
163
164	if (!hctx->nr_ctx)
165		return 0;
166
167	ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
168	if (ret)
169		return ret;
170
171	hctx_for_each_ctx(hctx, ctx, i) {
172		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
173		if (ret)
174			goto out;
175	}
176
177	return 0;
178out:
179	hctx_for_each_ctx(hctx, ctx, j) {
180		if (j < i)
181			kobject_del(&ctx->kobj);
182	}
183	kobject_del(&hctx->kobj);
184	return ret;
185}
186
187void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
188{
189	kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
190}
191
192void blk_mq_sysfs_deinit(struct request_queue *q)
193{
194	struct blk_mq_ctx *ctx;
195	int cpu;
196
197	for_each_possible_cpu(cpu) {
198		ctx = per_cpu_ptr(q->queue_ctx, cpu);
199		kobject_put(&ctx->kobj);
200	}
201	kobject_put(q->mq_kobj);
202}
203
204void blk_mq_sysfs_init(struct request_queue *q)
205{
206	struct blk_mq_ctx *ctx;
207	int cpu;
208
209	kobject_init(q->mq_kobj, &blk_mq_ktype);
210
211	for_each_possible_cpu(cpu) {
212		ctx = per_cpu_ptr(q->queue_ctx, cpu);
213
214		kobject_get(q->mq_kobj);
215		kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
216	}
217}
218
219int blk_mq_sysfs_register(struct gendisk *disk)
220{
221	struct request_queue *q = disk->queue;
222	struct blk_mq_hw_ctx *hctx;
223	unsigned long i, j;
224	int ret;
225
226	lockdep_assert_held(&q->sysfs_dir_lock);
227
228	ret = kobject_add(q->mq_kobj, &disk_to_dev(disk)->kobj, "mq");
229	if (ret < 0)
230		goto out;
231
232	kobject_uevent(q->mq_kobj, KOBJ_ADD);
233
234	queue_for_each_hw_ctx(q, hctx, i) {
235		ret = blk_mq_register_hctx(hctx);
236		if (ret)
237			goto unreg;
238	}
239
240	q->mq_sysfs_init_done = true;
241
242out:
243	return ret;
244
245unreg:
246	queue_for_each_hw_ctx(q, hctx, j) {
247		if (j < i)
248			blk_mq_unregister_hctx(hctx);
249	}
250
251	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
252	kobject_del(q->mq_kobj);
253	return ret;
254}
255
256void blk_mq_sysfs_unregister(struct gendisk *disk)
257{
258	struct request_queue *q = disk->queue;
259	struct blk_mq_hw_ctx *hctx;
260	unsigned long i;
261
262	lockdep_assert_held(&q->sysfs_dir_lock);
263
264	queue_for_each_hw_ctx(q, hctx, i)
265		blk_mq_unregister_hctx(hctx);
266
267	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
268	kobject_del(q->mq_kobj);
269
270	q->mq_sysfs_init_done = false;
271}
272
273void blk_mq_sysfs_unregister_hctxs(struct request_queue *q)
274{
275	struct blk_mq_hw_ctx *hctx;
276	unsigned long i;
277
278	mutex_lock(&q->sysfs_dir_lock);
279	if (!q->mq_sysfs_init_done)
280		goto unlock;
281
282	queue_for_each_hw_ctx(q, hctx, i)
283		blk_mq_unregister_hctx(hctx);
284
285unlock:
286	mutex_unlock(&q->sysfs_dir_lock);
287}
288
289int blk_mq_sysfs_register_hctxs(struct request_queue *q)
290{
291	struct blk_mq_hw_ctx *hctx;
292	unsigned long i;
293	int ret = 0;
294
295	mutex_lock(&q->sysfs_dir_lock);
296	if (!q->mq_sysfs_init_done)
297		goto unlock;
298
299	queue_for_each_hw_ctx(q, hctx, i) {
300		ret = blk_mq_register_hctx(hctx);
301		if (ret)
302			break;
303	}
304
305unlock:
306	mutex_unlock(&q->sysfs_dir_lock);
307
308	return ret;
309}