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Linux/block/blk-mq-sysfs.c

  1 #include <linux/kernel.h>
  2 #include <linux/module.h>
  3 #include <linux/backing-dev.h>
  4 #include <linux/bio.h>
  5 #include <linux/blkdev.h>
  6 #include <linux/mm.h>
  7 #include <linux/init.h>
  8 #include <linux/slab.h>
  9 #include <linux/workqueue.h>
 10 #include <linux/smp.h>
 11 
 12 #include <linux/blk-mq.h>
 13 #include "blk-mq.h"
 14 #include "blk-mq-tag.h"
 15 
 16 static void blk_mq_sysfs_release(struct kobject *kobj)
 17 {
 18 }
 19 
 20 struct blk_mq_ctx_sysfs_entry {
 21         struct attribute attr;
 22         ssize_t (*show)(struct blk_mq_ctx *, char *);
 23         ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
 24 };
 25 
 26 struct blk_mq_hw_ctx_sysfs_entry {
 27         struct attribute attr;
 28         ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
 29         ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
 30 };
 31 
 32 static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
 33                                  char *page)
 34 {
 35         struct blk_mq_ctx_sysfs_entry *entry;
 36         struct blk_mq_ctx *ctx;
 37         struct request_queue *q;
 38         ssize_t res;
 39 
 40         entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
 41         ctx = container_of(kobj, struct blk_mq_ctx, kobj);
 42         q = ctx->queue;
 43 
 44         if (!entry->show)
 45                 return -EIO;
 46 
 47         res = -ENOENT;
 48         mutex_lock(&q->sysfs_lock);
 49         if (!blk_queue_dying(q))
 50                 res = entry->show(ctx, page);
 51         mutex_unlock(&q->sysfs_lock);
 52         return res;
 53 }
 54 
 55 static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
 56                                   const char *page, size_t length)
 57 {
 58         struct blk_mq_ctx_sysfs_entry *entry;
 59         struct blk_mq_ctx *ctx;
 60         struct request_queue *q;
 61         ssize_t res;
 62 
 63         entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
 64         ctx = container_of(kobj, struct blk_mq_ctx, kobj);
 65         q = ctx->queue;
 66 
 67         if (!entry->store)
 68                 return -EIO;
 69 
 70         res = -ENOENT;
 71         mutex_lock(&q->sysfs_lock);
 72         if (!blk_queue_dying(q))
 73                 res = entry->store(ctx, page, length);
 74         mutex_unlock(&q->sysfs_lock);
 75         return res;
 76 }
 77 
 78 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
 79                                     struct attribute *attr, char *page)
 80 {
 81         struct blk_mq_hw_ctx_sysfs_entry *entry;
 82         struct blk_mq_hw_ctx *hctx;
 83         struct request_queue *q;
 84         ssize_t res;
 85 
 86         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
 87         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
 88         q = hctx->queue;
 89 
 90         if (!entry->show)
 91                 return -EIO;
 92 
 93         res = -ENOENT;
 94         mutex_lock(&q->sysfs_lock);
 95         if (!blk_queue_dying(q))
 96                 res = entry->show(hctx, page);
 97         mutex_unlock(&q->sysfs_lock);
 98         return res;
 99 }
100 
101 static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
102                                      struct attribute *attr, const char *page,
103                                      size_t length)
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->store)
115                 return -EIO;
116 
117         res = -ENOENT;
118         mutex_lock(&q->sysfs_lock);
119         if (!blk_queue_dying(q))
120                 res = entry->store(hctx, page, length);
121         mutex_unlock(&q->sysfs_lock);
122         return res;
123 }
124 
125 static ssize_t blk_mq_sysfs_dispatched_show(struct blk_mq_ctx *ctx, char *page)
126 {
127         return sprintf(page, "%lu %lu\n", ctx->rq_dispatched[1],
128                                 ctx->rq_dispatched[0]);
129 }
130 
131 static ssize_t blk_mq_sysfs_merged_show(struct blk_mq_ctx *ctx, char *page)
132 {
133         return sprintf(page, "%lu\n", ctx->rq_merged);
134 }
135 
136 static ssize_t blk_mq_sysfs_completed_show(struct blk_mq_ctx *ctx, char *page)
137 {
138         return sprintf(page, "%lu %lu\n", ctx->rq_completed[1],
139                                 ctx->rq_completed[0]);
140 }
141 
142 static ssize_t sysfs_list_show(char *page, struct list_head *list, char *msg)
143 {
144         struct request *rq;
145         int len = snprintf(page, PAGE_SIZE - 1, "%s:\n", msg);
146 
147         list_for_each_entry(rq, list, queuelist) {
148                 const int rq_len = 2 * sizeof(rq) + 2;
149 
150                 /* if the output will be truncated */
151                 if (PAGE_SIZE - 1 < len + rq_len) {
152                         /* backspacing if it can't hold '\t...\n' */
153                         if (PAGE_SIZE - 1 < len + 5)
154                                 len -= rq_len;
155                         len += snprintf(page + len, PAGE_SIZE - 1 - len,
156                                         "\t...\n");
157                         break;
158                 }
159                 len += snprintf(page + len, PAGE_SIZE - 1 - len,
160                                 "\t%p\n", rq);
161         }
162 
163         return len;
164 }
165 
166 static ssize_t blk_mq_sysfs_rq_list_show(struct blk_mq_ctx *ctx, char *page)
167 {
168         ssize_t ret;
169 
170         spin_lock(&ctx->lock);
171         ret = sysfs_list_show(page, &ctx->rq_list, "CTX pending");
172         spin_unlock(&ctx->lock);
173 
174         return ret;
175 }
176 
177 static ssize_t blk_mq_hw_sysfs_poll_show(struct blk_mq_hw_ctx *hctx, char *page)
178 {
179         return sprintf(page, "considered=%lu, invoked=%lu, success=%lu\n",
180                        hctx->poll_considered, hctx->poll_invoked,
181                        hctx->poll_success);
182 }
183 
184 static ssize_t blk_mq_hw_sysfs_poll_store(struct blk_mq_hw_ctx *hctx,
185                                           const char *page, size_t size)
186 {
187         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
188 
189         return size;
190 }
191 
192 static ssize_t blk_mq_hw_sysfs_queued_show(struct blk_mq_hw_ctx *hctx,
193                                            char *page)
194 {
195         return sprintf(page, "%lu\n", hctx->queued);
196 }
197 
198 static ssize_t blk_mq_hw_sysfs_run_show(struct blk_mq_hw_ctx *hctx, char *page)
199 {
200         return sprintf(page, "%lu\n", hctx->run);
201 }
202 
203 static ssize_t blk_mq_hw_sysfs_dispatched_show(struct blk_mq_hw_ctx *hctx,
204                                                char *page)
205 {
206         char *start_page = page;
207         int i;
208 
209         page += sprintf(page, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
210 
211         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
212                 unsigned int d = 1U << (i - 1);
213 
214                 page += sprintf(page, "%8u\t%lu\n", d, hctx->dispatched[i]);
215         }
216 
217         page += sprintf(page, "%8u+\t%lu\n", 1U << (i - 1),
218                                                 hctx->dispatched[i]);
219         return page - start_page;
220 }
221 
222 static ssize_t blk_mq_hw_sysfs_rq_list_show(struct blk_mq_hw_ctx *hctx,
223                                             char *page)
224 {
225         ssize_t ret;
226 
227         spin_lock(&hctx->lock);
228         ret = sysfs_list_show(page, &hctx->dispatch, "HCTX pending");
229         spin_unlock(&hctx->lock);
230 
231         return ret;
232 }
233 
234 static ssize_t blk_mq_hw_sysfs_tags_show(struct blk_mq_hw_ctx *hctx, char *page)
235 {
236         return blk_mq_tag_sysfs_show(hctx->tags, page);
237 }
238 
239 static ssize_t blk_mq_hw_sysfs_active_show(struct blk_mq_hw_ctx *hctx, char *page)
240 {
241         return sprintf(page, "%u\n", atomic_read(&hctx->nr_active));
242 }
243 
244 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
245 {
246         unsigned int i, first = 1;
247         ssize_t ret = 0;
248 
249         for_each_cpu(i, hctx->cpumask) {
250                 if (first)
251                         ret += sprintf(ret + page, "%u", i);
252                 else
253                         ret += sprintf(ret + page, ", %u", i);
254 
255                 first = 0;
256         }
257 
258         ret += sprintf(ret + page, "\n");
259         return ret;
260 }
261 
262 static void blk_mq_stat_clear(struct blk_mq_hw_ctx *hctx)
263 {
264         struct blk_mq_ctx *ctx;
265         unsigned int i;
266 
267         hctx_for_each_ctx(hctx, ctx, i) {
268                 blk_stat_init(&ctx->stat[BLK_STAT_READ]);
269                 blk_stat_init(&ctx->stat[BLK_STAT_WRITE]);
270         }
271 }
272 
273 static ssize_t blk_mq_hw_sysfs_stat_store(struct blk_mq_hw_ctx *hctx,
274                                           const char *page, size_t count)
275 {
276         blk_mq_stat_clear(hctx);
277         return count;
278 }
279 
280 static ssize_t print_stat(char *page, struct blk_rq_stat *stat, const char *pre)
281 {
282         return sprintf(page, "%s samples=%llu, mean=%lld, min=%lld, max=%lld\n",
283                         pre, (long long) stat->nr_samples,
284                         (long long) stat->mean, (long long) stat->min,
285                         (long long) stat->max);
286 }
287 
288 static ssize_t blk_mq_hw_sysfs_stat_show(struct blk_mq_hw_ctx *hctx, char *page)
289 {
290         struct blk_rq_stat stat[2];
291         ssize_t ret;
292 
293         blk_stat_init(&stat[BLK_STAT_READ]);
294         blk_stat_init(&stat[BLK_STAT_WRITE]);
295 
296         blk_hctx_stat_get(hctx, stat);
297 
298         ret = print_stat(page, &stat[BLK_STAT_READ], "read :");
299         ret += print_stat(page + ret, &stat[BLK_STAT_WRITE], "write:");
300         return ret;
301 }
302 
303 static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_dispatched = {
304         .attr = {.name = "dispatched", .mode = S_IRUGO },
305         .show = blk_mq_sysfs_dispatched_show,
306 };
307 static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_merged = {
308         .attr = {.name = "merged", .mode = S_IRUGO },
309         .show = blk_mq_sysfs_merged_show,
310 };
311 static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_completed = {
312         .attr = {.name = "completed", .mode = S_IRUGO },
313         .show = blk_mq_sysfs_completed_show,
314 };
315 static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_rq_list = {
316         .attr = {.name = "rq_list", .mode = S_IRUGO },
317         .show = blk_mq_sysfs_rq_list_show,
318 };
319 
320 static struct attribute *default_ctx_attrs[] = {
321         &blk_mq_sysfs_dispatched.attr,
322         &blk_mq_sysfs_merged.attr,
323         &blk_mq_sysfs_completed.attr,
324         &blk_mq_sysfs_rq_list.attr,
325         NULL,
326 };
327 
328 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_queued = {
329         .attr = {.name = "queued", .mode = S_IRUGO },
330         .show = blk_mq_hw_sysfs_queued_show,
331 };
332 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_run = {
333         .attr = {.name = "run", .mode = S_IRUGO },
334         .show = blk_mq_hw_sysfs_run_show,
335 };
336 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_dispatched = {
337         .attr = {.name = "dispatched", .mode = S_IRUGO },
338         .show = blk_mq_hw_sysfs_dispatched_show,
339 };
340 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_active = {
341         .attr = {.name = "active", .mode = S_IRUGO },
342         .show = blk_mq_hw_sysfs_active_show,
343 };
344 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_pending = {
345         .attr = {.name = "pending", .mode = S_IRUGO },
346         .show = blk_mq_hw_sysfs_rq_list_show,
347 };
348 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_tags = {
349         .attr = {.name = "tags", .mode = S_IRUGO },
350         .show = blk_mq_hw_sysfs_tags_show,
351 };
352 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
353         .attr = {.name = "cpu_list", .mode = S_IRUGO },
354         .show = blk_mq_hw_sysfs_cpus_show,
355 };
356 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_poll = {
357         .attr = {.name = "io_poll", .mode = S_IWUSR | S_IRUGO },
358         .show = blk_mq_hw_sysfs_poll_show,
359         .store = blk_mq_hw_sysfs_poll_store,
360 };
361 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_stat = {
362         .attr = {.name = "stats", .mode = S_IRUGO | S_IWUSR },
363         .show = blk_mq_hw_sysfs_stat_show,
364         .store = blk_mq_hw_sysfs_stat_store,
365 };
366 
367 static struct attribute *default_hw_ctx_attrs[] = {
368         &blk_mq_hw_sysfs_queued.attr,
369         &blk_mq_hw_sysfs_run.attr,
370         &blk_mq_hw_sysfs_dispatched.attr,
371         &blk_mq_hw_sysfs_pending.attr,
372         &blk_mq_hw_sysfs_tags.attr,
373         &blk_mq_hw_sysfs_cpus.attr,
374         &blk_mq_hw_sysfs_active.attr,
375         &blk_mq_hw_sysfs_poll.attr,
376         &blk_mq_hw_sysfs_stat.attr,
377         NULL,
378 };
379 
380 static const struct sysfs_ops blk_mq_sysfs_ops = {
381         .show   = blk_mq_sysfs_show,
382         .store  = blk_mq_sysfs_store,
383 };
384 
385 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
386         .show   = blk_mq_hw_sysfs_show,
387         .store  = blk_mq_hw_sysfs_store,
388 };
389 
390 static struct kobj_type blk_mq_ktype = {
391         .sysfs_ops      = &blk_mq_sysfs_ops,
392         .release        = blk_mq_sysfs_release,
393 };
394 
395 static struct kobj_type blk_mq_ctx_ktype = {
396         .sysfs_ops      = &blk_mq_sysfs_ops,
397         .default_attrs  = default_ctx_attrs,
398         .release        = blk_mq_sysfs_release,
399 };
400 
401 static struct kobj_type blk_mq_hw_ktype = {
402         .sysfs_ops      = &blk_mq_hw_sysfs_ops,
403         .default_attrs  = default_hw_ctx_attrs,
404         .release        = blk_mq_sysfs_release,
405 };
406 
407 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
408 {
409         struct blk_mq_ctx *ctx;
410         int i;
411 
412         if (!hctx->nr_ctx)
413                 return;
414 
415         hctx_for_each_ctx(hctx, ctx, i)
416                 kobject_del(&ctx->kobj);
417 
418         kobject_del(&hctx->kobj);
419 }
420 
421 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
422 {
423         struct request_queue *q = hctx->queue;
424         struct blk_mq_ctx *ctx;
425         int i, ret;
426 
427         if (!hctx->nr_ctx)
428                 return 0;
429 
430         ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
431         if (ret)
432                 return ret;
433 
434         hctx_for_each_ctx(hctx, ctx, i) {
435                 ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
436                 if (ret)
437                         break;
438         }
439 
440         return ret;
441 }
442 
443 static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
444 {
445         struct blk_mq_hw_ctx *hctx;
446         struct blk_mq_ctx *ctx;
447         int i, j;
448 
449         queue_for_each_hw_ctx(q, hctx, i) {
450                 blk_mq_unregister_hctx(hctx);
451 
452                 hctx_for_each_ctx(hctx, ctx, j)
453                         kobject_put(&ctx->kobj);
454 
455                 kobject_put(&hctx->kobj);
456         }
457 
458         kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
459         kobject_del(&q->mq_kobj);
460         kobject_put(&q->mq_kobj);
461 
462         kobject_put(&dev->kobj);
463 
464         q->mq_sysfs_init_done = false;
465 }
466 
467 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
468 {
469         blk_mq_disable_hotplug();
470         __blk_mq_unregister_dev(dev, q);
471         blk_mq_enable_hotplug();
472 }
473 
474 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
475 {
476         kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
477 }
478 
479 static void blk_mq_sysfs_init(struct request_queue *q)
480 {
481         struct blk_mq_ctx *ctx;
482         int cpu;
483 
484         kobject_init(&q->mq_kobj, &blk_mq_ktype);
485 
486         for_each_possible_cpu(cpu) {
487                 ctx = per_cpu_ptr(q->queue_ctx, cpu);
488                 kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
489         }
490 }
491 
492 int blk_mq_register_dev(struct device *dev, struct request_queue *q)
493 {
494         struct blk_mq_hw_ctx *hctx;
495         int ret, i;
496 
497         blk_mq_disable_hotplug();
498 
499         blk_mq_sysfs_init(q);
500 
501         ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
502         if (ret < 0)
503                 goto out;
504 
505         kobject_uevent(&q->mq_kobj, KOBJ_ADD);
506 
507         queue_for_each_hw_ctx(q, hctx, i) {
508                 ret = blk_mq_register_hctx(hctx);
509                 if (ret)
510                         break;
511         }
512 
513         if (ret)
514                 __blk_mq_unregister_dev(dev, q);
515         else
516                 q->mq_sysfs_init_done = true;
517 out:
518         blk_mq_enable_hotplug();
519 
520         return ret;
521 }
522 EXPORT_SYMBOL_GPL(blk_mq_register_dev);
523 
524 void blk_mq_sysfs_unregister(struct request_queue *q)
525 {
526         struct blk_mq_hw_ctx *hctx;
527         int i;
528 
529         if (!q->mq_sysfs_init_done)
530                 return;
531 
532         queue_for_each_hw_ctx(q, hctx, i)
533                 blk_mq_unregister_hctx(hctx);
534 }
535 
536 int blk_mq_sysfs_register(struct request_queue *q)
537 {
538         struct blk_mq_hw_ctx *hctx;
539         int i, ret = 0;
540 
541         if (!q->mq_sysfs_init_done)
542                 return ret;
543 
544         queue_for_each_hw_ctx(q, hctx, i) {
545                 ret = blk_mq_register_hctx(hctx);
546                 if (ret)
547                         break;
548         }
549 
550         return ret;
551 }
552 

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