block/blk-mq-sysfs.c

   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
  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
  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
  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         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
  48 struct 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
  54 struct 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
  60 static 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         res = -ENOENT;
  76         mutex_lock(&q->sysfs_lock);
  77         if (!blk_queue_dying(q))
  78                 res = entry->show(ctx, page);
  79         mutex_unlock(&q->sysfs_lock);
  80         return res;
  81 }
  82
  83 static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
  84                                   const char *page, size_t length)
  85 {
  86         struct blk_mq_ctx_sysfs_entry *entry;
  87         struct blk_mq_ctx *ctx;
  88         struct request_queue *q;
  89         ssize_t res;
  90
  91         entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
  92         ctx = container_of(kobj, struct blk_mq_ctx, kobj);
  93         q = ctx->queue;
  94
  95         if (!entry->store)
  96                 return -EIO;
  97
  98         res = -ENOENT;
  99         mutex_lock(&q->sysfs_lock);
 100         if (!blk_queue_dying(q))
 101                 res = entry->store(ctx, page, length);
 102         mutex_unlock(&q->sysfs_lock);
 103         return res;
 104 }
 105
 106 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
 107                                     struct attribute *attr, char *page)
 108 {
 109         struct blk_mq_hw_ctx_sysfs_entry *entry;
 110         struct blk_mq_hw_ctx *hctx;
 111         struct request_queue *q;
 112         ssize_t res;
 113
 114         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
 115         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
 116         q = hctx->queue;
 117
 118         if (!entry->show)
 119                 return -EIO;
 120
 121         res = -ENOENT;
 122         mutex_lock(&q->sysfs_lock);
 123         if (!blk_queue_dying(q))
 124                 res = entry->show(hctx, page);
 125         mutex_unlock(&q->sysfs_lock);
 126         return res;
 127 }
 128
 129 static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
 130                                      struct attribute *attr, const char *page,
 131                                      size_t length)
 132 {
 133         struct blk_mq_hw_ctx_sysfs_entry *entry;
 134         struct blk_mq_hw_ctx *hctx;
 135         struct request_queue *q;
 136         ssize_t res;
 137
 138         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
 139         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
 140         q = hctx->queue;
 141
 142         if (!entry->store)
 143                 return -EIO;
 144
 145         res = -ENOENT;
 146         mutex_lock(&q->sysfs_lock);
 147         if (!blk_queue_dying(q))
 148                 res = entry->store(hctx, page, length);
 149         mutex_unlock(&q->sysfs_lock);
 150         return res;
 151 }
 152
 153 static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
 154                                             char *page)
 155 {
 156         return sprintf(page, "%u\n", hctx->tags->nr_tags);
 157 }
 158
 159 static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
 160                                                      char *page)
 161 {
 162         return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
 163 }
 164
 165 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 166 {
 167         unsigned int i, first = 1;
 168         ssize_t ret = 0;
 169
 170         for_each_cpu(i, hctx->cpumask) {
 171                 if (first)
 172                         ret += sprintf(ret + page, "%u", i);
 173                 else
 174                         ret += sprintf(ret + page, ", %u", i);
 175
 176                 first = 0;
 177         }
 178
 179         ret += sprintf(ret + page, "\n");
 180         return ret;
 181 }
 182
 183 static struct attribute *default_ctx_attrs[] = {
 184         NULL,
 185 };
 186
 187 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
 188         .attr = {.name = "nr_tags", .mode = 0444 },
 189         .show = blk_mq_hw_sysfs_nr_tags_show,
 190 };
 191 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
 192         .attr = {.name = "nr_reserved_tags", .mode = 0444 },
 193         .show = blk_mq_hw_sysfs_nr_reserved_tags_show,
 194 };
 195 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
 196         .attr = {.name = "cpu_list", .mode = 0444 },
 197         .show = blk_mq_hw_sysfs_cpus_show,
 198 };
 199
 200 static struct attribute *default_hw_ctx_attrs[] = {
 201         &blk_mq_hw_sysfs_nr_tags.attr,
 202         &blk_mq_hw_sysfs_nr_reserved_tags.attr,
 203         &blk_mq_hw_sysfs_cpus.attr,
 204         NULL,
 205 };
 206
 207 static const struct sysfs_ops blk_mq_sysfs_ops = {
 208         .show   = blk_mq_sysfs_show,
 209         .store  = blk_mq_sysfs_store,
 210 };
 211
 212 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
 213         .show   = blk_mq_hw_sysfs_show,
 214         .store  = blk_mq_hw_sysfs_store,
 215 };
 216
 217 static struct kobj_type blk_mq_ktype = {
 218         .sysfs_ops      = &blk_mq_sysfs_ops,
 219         .release        = blk_mq_sysfs_release,
 220 };
 221
 222 static struct kobj_type blk_mq_ctx_ktype = {
 223         .sysfs_ops      = &blk_mq_sysfs_ops,
 224         .default_attrs  = default_ctx_attrs,
 225         .release        = blk_mq_ctx_sysfs_release,
 226 };
 227
 228 static struct kobj_type blk_mq_hw_ktype = {
 229         .sysfs_ops      = &blk_mq_hw_sysfs_ops,
 230         .default_attrs  = default_hw_ctx_attrs,
 231         .release        = blk_mq_hw_sysfs_release,
 232 };
 233
 234 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 235 {
 236         struct blk_mq_ctx *ctx;
 237         int i;
 238
 239         if (!hctx->nr_ctx)
 240                 return;
 241
 242         hctx_for_each_ctx(hctx, ctx, i)
 243                 kobject_del(&ctx->kobj);
 244
 245         kobject_del(&hctx->kobj);
 246 }
 247
 248 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 249 {
 250         struct request_queue *q = hctx->queue;
 251         struct blk_mq_ctx *ctx;
 252         int i, ret;
 253
 254         if (!hctx->nr_ctx)
 255                 return 0;
 256
 257         ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
 258         if (ret)
 259                 return ret;
 260
 261         hctx_for_each_ctx(hctx, ctx, i) {
 262                 ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
 263                 if (ret)
 264                         break;
 265         }
 266
 267         return ret;
 268 }
 269
 270 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 271 {
 272         struct blk_mq_hw_ctx *hctx;
 273         int i;
 274
 275         lockdep_assert_held(&q->sysfs_lock);
 276
 277         queue_for_each_hw_ctx(q, hctx, i)
 278                 blk_mq_unregister_hctx(hctx);
 279
 280         kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
 281         kobject_del(q->mq_kobj);
 282         kobject_put(&dev->kobj);
 283
 284         q->mq_sysfs_init_done = false;
 285 }
 286
 287 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
 288 {
 289         kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
 290 }
 291
 292 void blk_mq_sysfs_deinit(struct request_queue *q)
 293 {
 294         struct blk_mq_ctx *ctx;
 295         int cpu;
 296
 297         for_each_possible_cpu(cpu) {
 298                 ctx = per_cpu_ptr(q->queue_ctx, cpu);
 299                 kobject_put(&ctx->kobj);
 300         }
 301         kobject_put(q->mq_kobj);
 302 }
 303
 304 void blk_mq_sysfs_init(struct request_queue *q)
 305 {
 306         struct blk_mq_ctx *ctx;
 307         int cpu;
 308
 309         kobject_init(q->mq_kobj, &blk_mq_ktype);
 310
 311         for_each_possible_cpu(cpu) {
 312                 ctx = per_cpu_ptr(q->queue_ctx, cpu);
 313
 314                 kobject_get(q->mq_kobj);
 315                 kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
 316         }
 317 }
 318
 319 int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
 320 {
 321         struct blk_mq_hw_ctx *hctx;
 322         int ret, i;
 323
 324         WARN_ON_ONCE(!q->kobj.parent);
 325         lockdep_assert_held(&q->sysfs_lock);
 326
 327         ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
 328         if (ret < 0)
 329                 goto out;
 330
 331         kobject_uevent(q->mq_kobj, KOBJ_ADD);
 332
 333         queue_for_each_hw_ctx(q, hctx, i) {
 334                 ret = blk_mq_register_hctx(hctx);
 335                 if (ret)
 336                         goto unreg;
 337         }
 338
 339         q->mq_sysfs_init_done = true;
 340
 341 out:
 342         return ret;
 343
 344 unreg:
 345         while (--i >= 0)
 346                 blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
 347
 348         kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
 349         kobject_del(q->mq_kobj);
 350         kobject_put(&dev->kobj);
 351         return ret;
 352 }
 353
 354 int blk_mq_register_dev(struct device *dev, struct request_queue *q)
 355 {
 356         int ret;
 357
 358         mutex_lock(&q->sysfs_lock);
 359         ret = __blk_mq_register_dev(dev, q);
 360         mutex_unlock(&q->sysfs_lock);
 361
 362         return ret;
 363 }
 364
 365 void blk_mq_sysfs_unregister(struct request_queue *q)
 366 {
 367         struct blk_mq_hw_ctx *hctx;
 368         int i;
 369
 370         mutex_lock(&q->sysfs_lock);
 371         if (!q->mq_sysfs_init_done)
 372                 goto unlock;
 373
 374         queue_for_each_hw_ctx(q, hctx, i)
 375                 blk_mq_unregister_hctx(hctx);
 376
 377 unlock:
 378         mutex_unlock(&q->sysfs_lock);
 379 }
 380
 381 int blk_mq_sysfs_register(struct request_queue *q)
 382 {
 383         struct blk_mq_hw_ctx *hctx;
 384         int i, ret = 0;
 385
 386         mutex_lock(&q->sysfs_lock);
 387         if (!q->mq_sysfs_init_done)
 388                 goto unlock;
 389
 390         queue_for_each_hw_ctx(q, hctx, i) {
 391                 ret = blk_mq_register_hctx(hctx);
 392                 if (ret)
 393                         break;
 394         }
 395
 396 unlock:
 397         mutex_unlock(&q->sysfs_lock);
 398
 399         return ret;
 400 }