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
16 static 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
24 static 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
32 static 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
44 struct blk_mq_hw_ctx_sysfs_entry {
45 struct attribute attr;
46 ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
47 };
48
49 static 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
70 static 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
76 static 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
82 static 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
105 static 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 };
109 static 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 };
113 static 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
118 static 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 };
124 ATTRIBUTE_GROUPS(default_hw_ctx);
125
126 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
127 .show = blk_mq_hw_sysfs_show,
128 };
129
130 static const struct kobj_type blk_mq_ktype = {
131 .release = blk_mq_sysfs_release,
132 };
133
134 static const struct kobj_type blk_mq_ctx_ktype = {
135 .release = blk_mq_ctx_sysfs_release,
136 };
137
138 static 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
144 static 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
158 static 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;
178 out:
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
187 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
188 {
189 kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
190 }
191
192 void 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
204 void 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
219 int 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
242 out:
243 return ret;
244
245 unreg:
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
256 void 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
273 void 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
285 unlock:
286 mutex_unlock(&q->sysfs_dir_lock);
287 }
288
289 int 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
305 unlock:
306 mutex_unlock(&q->sysfs_dir_lock);
307
308 return ret;
309 }
310
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