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 static void blk_mq_hw_sysfs_release(struct kobject *kobj)
  21 {
  22         struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
  23                                                   kobj);
  24         free_cpumask_var(hctx->cpumask);
  25         kfree(hctx->ctxs);
  26         kfree(hctx);
  27 }
  28
  29 struct blk_mq_ctx_sysfs_entry {
  30         struct attribute attr;
  31         ssize_t (*show)(struct blk_mq_ctx *, char *);
  32         ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
  33 };
  34
  35 struct blk_mq_hw_ctx_sysfs_entry {
  36         struct attribute attr;
  37         ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
  38         ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
  39 };
  40
  41 static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
  42                                  char *page)
  43 {
  44         struct blk_mq_ctx_sysfs_entry *entry;
  45         struct blk_mq_ctx *ctx;
  46         struct request_queue *q;
  47         ssize_t res;
  48
  49         entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
  50         ctx = container_of(kobj, struct blk_mq_ctx, kobj);
  51         q = ctx->queue;
  52
  53         if (!entry->show)
  54                 return -EIO;
  55
  56         res = -ENOENT;
  57         mutex_lock(&q->sysfs_lock);
  58         if (!blk_queue_dying(q))
  59                 res = entry->show(ctx, page);
  60         mutex_unlock(&q->sysfs_lock);
  61         return res;
  62 }
  63
  64 static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
  65                                   const char *page, size_t length)
  66 {
  67         struct blk_mq_ctx_sysfs_entry *entry;
  68         struct blk_mq_ctx *ctx;
  69         struct request_queue *q;
  70         ssize_t res;
  71
  72         entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
  73         ctx = container_of(kobj, struct blk_mq_ctx, kobj);
  74         q = ctx->queue;
  75
  76         if (!entry->store)
  77                 return -EIO;
  78
  79         res = -ENOENT;
  80         mutex_lock(&q->sysfs_lock);
  81         if (!blk_queue_dying(q))
  82                 res = entry->store(ctx, page, length);
  83         mutex_unlock(&q->sysfs_lock);
  84         return res;
  85 }
  86
  87 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
  88                                     struct attribute *attr, char *page)
  89 {
  90         struct blk_mq_hw_ctx_sysfs_entry *entry;
  91         struct blk_mq_hw_ctx *hctx;
  92         struct request_queue *q;
  93         ssize_t res;
  94
  95         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
  96         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
  97         q = hctx->queue;
  98
  99         if (!entry->show)
 100                 return -EIO;
 101
 102         res = -ENOENT;
 103         mutex_lock(&q->sysfs_lock);
 104         if (!blk_queue_dying(q))
 105                 res = entry->show(hctx, page);
 106         mutex_unlock(&q->sysfs_lock);
 107         return res;
 108 }
 109
 110 static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
 111                                      struct attribute *attr, const char *page,
 112                                      size_t length)
 113 {
 114         struct blk_mq_hw_ctx_sysfs_entry *entry;
 115         struct blk_mq_hw_ctx *hctx;
 116         struct request_queue *q;
 117         ssize_t res;
 118
 119         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
 120         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
 121         q = hctx->queue;
 122
 123         if (!entry->store)
 124                 return -EIO;
 125
 126         res = -ENOENT;
 127         mutex_lock(&q->sysfs_lock);
 128         if (!blk_queue_dying(q))
 129                 res = entry->store(hctx, page, length);
 130         mutex_unlock(&q->sysfs_lock);
 131         return res;
 132 }
 133
 134 static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
 135                                             char *page)
 136 {
 137         return sprintf(page, "%u\n", hctx->tags->nr_tags);
 138 }
 139
 140 static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
 141                                                      char *page)
 142 {
 143         return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
 144 }
 145
 146 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 147 {
 148         const size_t size = PAGE_SIZE - 1;
 149         unsigned int i, first = 1;
 150         int ret = 0, pos = 0;
 151
 152         for_each_cpu(i, hctx->cpumask) {
 153                 if (first)
 154                         ret = snprintf(pos + page, size - pos, "%u", i);
 155                 else
 156                         ret = snprintf(pos + page, size - pos, ", %u", i);
 157
 158                 if (ret >= size - pos)
 159                         break;
 160
 161                 first = 0;
 162                 pos += ret;
 163         }
 164
 165         ret = snprintf(pos + page, size - pos, "\n");
 166         return pos + ret;
 167 }
 168
 169 static struct attribute *default_ctx_attrs[] = {
 170         NULL,
 171 };
 172
 173 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
 174         .attr = {.name = "nr_tags", .mode = S_IRUGO },
 175         .show = blk_mq_hw_sysfs_nr_tags_show,
 176 };
 177 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
 178         .attr = {.name = "nr_reserved_tags", .mode = S_IRUGO },
 179         .show = blk_mq_hw_sysfs_nr_reserved_tags_show,
 180 };
 181 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
 182         .attr = {.name = "cpu_list", .mode = S_IRUGO },
 183         .show = blk_mq_hw_sysfs_cpus_show,
 184 };
 185
 186 static struct attribute *default_hw_ctx_attrs[] = {
 187         &blk_mq_hw_sysfs_nr_tags.attr,
 188         &blk_mq_hw_sysfs_nr_reserved_tags.attr,
 189         &blk_mq_hw_sysfs_cpus.attr,
 190         NULL,
 191 };
 192
 193 static const struct sysfs_ops blk_mq_sysfs_ops = {
 194         .show   = blk_mq_sysfs_show,
 195         .store  = blk_mq_sysfs_store,
 196 };
 197
 198 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
 199         .show   = blk_mq_hw_sysfs_show,
 200         .store  = blk_mq_hw_sysfs_store,
 201 };
 202
 203 static struct kobj_type blk_mq_ktype = {
 204         .sysfs_ops      = &blk_mq_sysfs_ops,
 205         .release        = blk_mq_sysfs_release,
 206 };
 207
 208 static struct kobj_type blk_mq_ctx_ktype = {
 209         .sysfs_ops      = &blk_mq_sysfs_ops,
 210         .default_attrs  = default_ctx_attrs,
 211         .release        = blk_mq_sysfs_release,
 212 };
 213
 214 static struct kobj_type blk_mq_hw_ktype = {
 215         .sysfs_ops      = &blk_mq_hw_sysfs_ops,
 216         .default_attrs  = default_hw_ctx_attrs,
 217         .release        = blk_mq_hw_sysfs_release,
 218 };
 219
 220 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 221 {
 222         struct blk_mq_ctx *ctx;
 223         int i;
 224
 225         if (!hctx->nr_ctx)
 226                 return;
 227
 228         hctx_for_each_ctx(hctx, ctx, i)
 229                 kobject_del(&ctx->kobj);
 230
 231         kobject_del(&hctx->kobj);
 232 }
 233
 234 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 235 {
 236         struct request_queue *q = hctx->queue;
 237         struct blk_mq_ctx *ctx;
 238         int i, ret;
 239
 240         if (!hctx->nr_ctx)
 241                 return 0;
 242
 243         ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
 244         if (ret)
 245                 return ret;
 246
 247         hctx_for_each_ctx(hctx, ctx, i) {
 248                 ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
 249                 if (ret)
 250                         break;
 251         }
 252
 253         return ret;
 254 }
 255
 256 static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 257 {
 258         struct blk_mq_hw_ctx *hctx;
 259         int i;
 260
 261         lockdep_assert_held(&q->sysfs_lock);
 262
 263         queue_for_each_hw_ctx(q, hctx, i)
 264                 blk_mq_unregister_hctx(hctx);
 265
 266         kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
 267         kobject_del(&q->mq_kobj);
 268         kobject_put(&dev->kobj);
 269
 270         q->mq_sysfs_init_done = false;
 271 }
 272
 273 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 274 {
 275         mutex_lock(&q->sysfs_lock);
 276         __blk_mq_unregister_dev(dev, q);
 277         mutex_unlock(&q->sysfs_lock);
 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                 kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
 307         }
 308 }
 309
 310 int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
 311 {
 312         struct blk_mq_hw_ctx *hctx;
 313         int ret, i;
 314
 315         WARN_ON_ONCE(!q->kobj.parent);
 316         lockdep_assert_held(&q->sysfs_lock);
 317
 318         ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
 319         if (ret < 0)
 320                 goto out;
 321
 322         kobject_uevent(&q->mq_kobj, KOBJ_ADD);
 323
 324         queue_for_each_hw_ctx(q, hctx, i) {
 325                 ret = blk_mq_register_hctx(hctx);
 326                 if (ret)
 327                         goto unreg;
 328         }
 329
 330         q->mq_sysfs_init_done = true;
 331
 332 out:
 333         return ret;
 334
 335 unreg:
 336         while (--i >= 0)
 337                 blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
 338
 339         kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
 340         kobject_del(&q->mq_kobj);
 341         kobject_put(&dev->kobj);
 342         return ret;
 343 }
 344
 345 int blk_mq_register_dev(struct device *dev, struct request_queue *q)
 346 {
 347         int ret;
 348
 349         mutex_lock(&q->sysfs_lock);
 350         ret = __blk_mq_register_dev(dev, q);
 351         mutex_unlock(&q->sysfs_lock);
 352
 353         return ret;
 354 }
 355 EXPORT_SYMBOL_GPL(blk_mq_register_dev);
 356
 357 void blk_mq_sysfs_unregister(struct request_queue *q)
 358 {
 359         struct blk_mq_hw_ctx *hctx;
 360         int i;
 361
 362         mutex_lock(&q->sysfs_lock);
 363         if (!q->mq_sysfs_init_done)
 364                 goto unlock;
 365
 366         queue_for_each_hw_ctx(q, hctx, i)
 367                 blk_mq_unregister_hctx(hctx);
 368
 369 unlock:
 370         mutex_unlock(&q->sysfs_lock);
 371 }
 372
 373 int blk_mq_sysfs_register(struct request_queue *q)
 374 {
 375         struct blk_mq_hw_ctx *hctx;
 376         int i, ret = 0;
 377
 378         mutex_lock(&q->sysfs_lock);
 379         if (!q->mq_sysfs_init_done)
 380                 goto unlock;
 381
 382         queue_for_each_hw_ctx(q, hctx, i) {
 383                 ret = blk_mq_register_hctx(hctx);
 384                 if (ret)
 385                         break;
 386         }
 387
 388 unlock:
 389         mutex_unlock(&q->sysfs_lock);
 390
 391         return ret;
 392 }