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_hw_ctx_sysfs_entry {
  49         struct attribute attr;
  50         ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
  51         ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
  52 };
  53
  54 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
  55                                     struct attribute *attr, char *page)
  56 {
  57         struct blk_mq_hw_ctx_sysfs_entry *entry;
  58         struct blk_mq_hw_ctx *hctx;
  59         struct request_queue *q;
  60         ssize_t res;
  61
  62         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
  63         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
  64         q = hctx->queue;
  65
  66         if (!entry->show)
  67                 return -EIO;
  68
  69         mutex_lock(&q->sysfs_lock);
  70         res = entry->show(hctx, page);
  71         mutex_unlock(&q->sysfs_lock);
  72         return res;
  73 }
  74
  75 static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
  76                                      struct attribute *attr, const char *page,
  77                                      size_t length)
  78 {
  79         struct blk_mq_hw_ctx_sysfs_entry *entry;
  80         struct blk_mq_hw_ctx *hctx;
  81         struct request_queue *q;
  82         ssize_t res;
  83
  84         entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
  85         hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
  86         q = hctx->queue;
  87
  88         if (!entry->store)
  89                 return -EIO;
  90
  91         mutex_lock(&q->sysfs_lock);
  92         res = entry->store(hctx, page, length);
  93         mutex_unlock(&q->sysfs_lock);
  94         return res;
  95 }
  96
  97 static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
  98                                             char *page)
  99 {
 100         return sprintf(page, "%u\n", hctx->tags->nr_tags);
 101 }
 102
 103 static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
 104                                                      char *page)
 105 {
 106         return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
 107 }
 108
 109 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 110 {
 111         const size_t size = PAGE_SIZE - 1;
 112         unsigned int i, first = 1;
 113         int ret = 0, pos = 0;
 114
 115         for_each_cpu(i, hctx->cpumask) {
 116                 if (first)
 117                         ret = snprintf(pos + page, size - pos, "%u", i);
 118                 else
 119                         ret = snprintf(pos + page, size - pos, ", %u", i);
 120
 121                 if (ret >= size - pos)
 122                         break;
 123
 124                 first = 0;
 125                 pos += ret;
 126         }
 127
 128         ret = snprintf(pos + page, size + 1 - pos, "\n");
 129         return pos + ret;
 130 }
 131
 132 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
 133         .attr = {.name = "nr_tags", .mode = 0444 },
 134         .show = blk_mq_hw_sysfs_nr_tags_show,
 135 };
 136 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
 137         .attr = {.name = "nr_reserved_tags", .mode = 0444 },
 138         .show = blk_mq_hw_sysfs_nr_reserved_tags_show,
 139 };
 140 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
 141         .attr = {.name = "cpu_list", .mode = 0444 },
 142         .show = blk_mq_hw_sysfs_cpus_show,
 143 };
 144
 145 static struct attribute *default_hw_ctx_attrs[] = {
 146         &blk_mq_hw_sysfs_nr_tags.attr,
 147         &blk_mq_hw_sysfs_nr_reserved_tags.attr,
 148         &blk_mq_hw_sysfs_cpus.attr,
 149         NULL,
 150 };
 151 ATTRIBUTE_GROUPS(default_hw_ctx);
 152
 153 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
 154         .show   = blk_mq_hw_sysfs_show,
 155         .store  = blk_mq_hw_sysfs_store,
 156 };
 157
 158 static struct kobj_type blk_mq_ktype = {
 159         .release        = blk_mq_sysfs_release,
 160 };
 161
 162 static struct kobj_type blk_mq_ctx_ktype = {
 163         .release        = blk_mq_ctx_sysfs_release,
 164 };
 165
 166 static struct kobj_type blk_mq_hw_ktype = {
 167         .sysfs_ops      = &blk_mq_hw_sysfs_ops,
 168         .default_groups = default_hw_ctx_groups,
 169         .release        = blk_mq_hw_sysfs_release,
 170 };
 171
 172 static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 173 {
 174         struct blk_mq_ctx *ctx;
 175         int i;
 176
 177         if (!hctx->nr_ctx)
 178                 return;
 179
 180         hctx_for_each_ctx(hctx, ctx, i)
 181                 kobject_del(&ctx->kobj);
 182
 183         kobject_del(&hctx->kobj);
 184 }
 185
 186 static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
 187 {
 188         struct request_queue *q = hctx->queue;
 189         struct blk_mq_ctx *ctx;
 190         int i, ret;
 191
 192         if (!hctx->nr_ctx)
 193                 return 0;
 194
 195         ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
 196         if (ret)
 197                 return ret;
 198
 199         hctx_for_each_ctx(hctx, ctx, i) {
 200                 ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
 201                 if (ret)
 202                         break;
 203         }
 204
 205         return ret;
 206 }
 207
 208 void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
 209 {
 210         struct blk_mq_hw_ctx *hctx;
 211         int i;
 212
 213         lockdep_assert_held(&q->sysfs_dir_lock);
 214
 215         queue_for_each_hw_ctx(q, hctx, i)
 216                 blk_mq_unregister_hctx(hctx);
 217
 218         kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
 219         kobject_del(q->mq_kobj);
 220         kobject_put(&dev->kobj);
 221
 222         q->mq_sysfs_init_done = false;
 223 }
 224
 225 void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
 226 {
 227         kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
 228 }
 229
 230 void blk_mq_sysfs_deinit(struct request_queue *q)
 231 {
 232         struct blk_mq_ctx *ctx;
 233         int cpu;
 234
 235         for_each_possible_cpu(cpu) {
 236                 ctx = per_cpu_ptr(q->queue_ctx, cpu);
 237                 kobject_put(&ctx->kobj);
 238         }
 239         kobject_put(q->mq_kobj);
 240 }
 241
 242 void blk_mq_sysfs_init(struct request_queue *q)
 243 {
 244         struct blk_mq_ctx *ctx;
 245         int cpu;
 246
 247         kobject_init(q->mq_kobj, &blk_mq_ktype);
 248
 249         for_each_possible_cpu(cpu) {
 250                 ctx = per_cpu_ptr(q->queue_ctx, cpu);
 251
 252                 kobject_get(q->mq_kobj);
 253                 kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
 254         }
 255 }
 256
 257 int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
 258 {
 259         struct blk_mq_hw_ctx *hctx;
 260         int ret, i;
 261
 262         WARN_ON_ONCE(!q->kobj.parent);
 263         lockdep_assert_held(&q->sysfs_dir_lock);
 264
 265         ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
 266         if (ret < 0)
 267                 goto out;
 268
 269         kobject_uevent(q->mq_kobj, KOBJ_ADD);
 270
 271         queue_for_each_hw_ctx(q, hctx, i) {
 272                 ret = blk_mq_register_hctx(hctx);
 273                 if (ret)
 274                         goto unreg;
 275         }
 276
 277         q->mq_sysfs_init_done = true;
 278
 279 out:
 280         return ret;
 281
 282 unreg:
 283         while (--i >= 0)
 284                 blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
 285
 286         kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
 287         kobject_del(q->mq_kobj);
 288         kobject_put(&dev->kobj);
 289         return ret;
 290 }
 291
 292 void blk_mq_sysfs_unregister(struct request_queue *q)
 293 {
 294         struct blk_mq_hw_ctx *hctx;
 295         int i;
 296
 297         mutex_lock(&q->sysfs_dir_lock);
 298         if (!q->mq_sysfs_init_done)
 299                 goto unlock;
 300
 301         queue_for_each_hw_ctx(q, hctx, i)
 302                 blk_mq_unregister_hctx(hctx);
 303
 304 unlock:
 305         mutex_unlock(&q->sysfs_dir_lock);
 306 }
 307
 308 int blk_mq_sysfs_register(struct request_queue *q)
 309 {
 310         struct blk_mq_hw_ctx *hctx;
 311         int i, ret = 0;
 312
 313         mutex_lock(&q->sysfs_dir_lock);
 314         if (!q->mq_sysfs_init_done)
 315                 goto unlock;
 316
 317         queue_for_each_hw_ctx(q, hctx, i) {
 318                 ret = blk_mq_register_hctx(hctx);
 319                 if (ret)
 320                         break;
 321         }
 322
 323 unlock:
 324         mutex_unlock(&q->sysfs_dir_lock);
 325
 326         return ret;
 327 }