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