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