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![Jens Axboe](/assets/img/avatar_default.png)
If we fail registering any of the hardware queues, we call into blk_mq_unregister_disk() with the hotplug mutex already held. Since blk_mq_unregister_disk() attempts to acquire the same mutex, we end up in a less than happy place. Reported-by: Jinpu Wang <jinpu.wang@profitbricks.com> Signed-off-by: Jens Axboe <axboe@fb.com>
494 lines
11 KiB
C
494 lines
11 KiB
C
#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/smp.h>
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#include <linux/blk-mq.h>
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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static void blk_mq_sysfs_release(struct kobject *kobj)
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{
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}
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struct blk_mq_ctx_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct blk_mq_ctx *, char *);
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ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
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};
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struct blk_mq_hw_ctx_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
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ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
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};
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static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
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char *page)
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{
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struct blk_mq_ctx_sysfs_entry *entry;
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struct blk_mq_ctx *ctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
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ctx = container_of(kobj, struct blk_mq_ctx, kobj);
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q = ctx->queue;
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if (!entry->show)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->show(ctx, page);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
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const char *page, size_t length)
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{
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struct blk_mq_ctx_sysfs_entry *entry;
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struct blk_mq_ctx *ctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
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ctx = container_of(kobj, struct blk_mq_ctx, kobj);
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q = ctx->queue;
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if (!entry->store)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->store(ctx, page, length);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
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struct attribute *attr, char *page)
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{
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struct blk_mq_hw_ctx_sysfs_entry *entry;
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struct blk_mq_hw_ctx *hctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
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hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
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q = hctx->queue;
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if (!entry->show)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->show(hctx, page);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
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struct attribute *attr, const char *page,
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size_t length)
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{
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struct blk_mq_hw_ctx_sysfs_entry *entry;
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struct blk_mq_hw_ctx *hctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
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hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
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q = hctx->queue;
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if (!entry->store)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->store(hctx, page, length);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_sysfs_dispatched_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu %lu\n", ctx->rq_dispatched[1],
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ctx->rq_dispatched[0]);
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}
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static ssize_t blk_mq_sysfs_merged_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu\n", ctx->rq_merged);
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}
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static ssize_t blk_mq_sysfs_completed_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu %lu\n", ctx->rq_completed[1],
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ctx->rq_completed[0]);
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}
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static ssize_t sysfs_list_show(char *page, struct list_head *list, char *msg)
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{
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struct request *rq;
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int len = snprintf(page, PAGE_SIZE - 1, "%s:\n", msg);
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list_for_each_entry(rq, list, queuelist) {
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const int rq_len = 2 * sizeof(rq) + 2;
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/* if the output will be truncated */
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if (PAGE_SIZE - 1 < len + rq_len) {
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/* backspacing if it can't hold '\t...\n' */
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if (PAGE_SIZE - 1 < len + 5)
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len -= rq_len;
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len += snprintf(page + len, PAGE_SIZE - 1 - len,
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"\t...\n");
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break;
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}
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len += snprintf(page + len, PAGE_SIZE - 1 - len,
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"\t%p\n", rq);
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}
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return len;
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}
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static ssize_t blk_mq_sysfs_rq_list_show(struct blk_mq_ctx *ctx, char *page)
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{
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ssize_t ret;
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spin_lock(&ctx->lock);
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ret = sysfs_list_show(page, &ctx->rq_list, "CTX pending");
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spin_unlock(&ctx->lock);
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return ret;
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}
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static ssize_t blk_mq_hw_sysfs_poll_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return sprintf(page, "invoked=%lu, success=%lu\n", hctx->poll_invoked, hctx->poll_success);
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}
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static ssize_t blk_mq_hw_sysfs_queued_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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return sprintf(page, "%lu\n", hctx->queued);
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}
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static ssize_t blk_mq_hw_sysfs_run_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return sprintf(page, "%lu\n", hctx->run);
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}
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static ssize_t blk_mq_hw_sysfs_dispatched_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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char *start_page = page;
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int i;
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page += sprintf(page, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
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for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER; i++) {
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unsigned long d = 1U << (i - 1);
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page += sprintf(page, "%8lu\t%lu\n", d, hctx->dispatched[i]);
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}
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return page - start_page;
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}
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static ssize_t blk_mq_hw_sysfs_rq_list_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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ssize_t ret;
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spin_lock(&hctx->lock);
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ret = sysfs_list_show(page, &hctx->dispatch, "HCTX pending");
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spin_unlock(&hctx->lock);
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return ret;
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}
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static ssize_t blk_mq_hw_sysfs_tags_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return blk_mq_tag_sysfs_show(hctx->tags, page);
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}
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static ssize_t blk_mq_hw_sysfs_active_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return sprintf(page, "%u\n", atomic_read(&hctx->nr_active));
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}
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static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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unsigned int i, first = 1;
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ssize_t ret = 0;
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for_each_cpu(i, hctx->cpumask) {
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if (first)
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ret += sprintf(ret + page, "%u", i);
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else
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ret += sprintf(ret + page, ", %u", i);
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first = 0;
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}
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ret += sprintf(ret + page, "\n");
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return ret;
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}
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_dispatched = {
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.attr = {.name = "dispatched", .mode = S_IRUGO },
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.show = blk_mq_sysfs_dispatched_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_merged = {
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.attr = {.name = "merged", .mode = S_IRUGO },
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.show = blk_mq_sysfs_merged_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_completed = {
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.attr = {.name = "completed", .mode = S_IRUGO },
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.show = blk_mq_sysfs_completed_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_rq_list = {
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.attr = {.name = "rq_list", .mode = S_IRUGO },
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.show = blk_mq_sysfs_rq_list_show,
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};
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static struct attribute *default_ctx_attrs[] = {
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&blk_mq_sysfs_dispatched.attr,
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&blk_mq_sysfs_merged.attr,
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&blk_mq_sysfs_completed.attr,
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&blk_mq_sysfs_rq_list.attr,
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NULL,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_queued = {
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.attr = {.name = "queued", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_queued_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_run = {
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.attr = {.name = "run", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_run_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_dispatched = {
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.attr = {.name = "dispatched", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_dispatched_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_active = {
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.attr = {.name = "active", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_active_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_pending = {
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.attr = {.name = "pending", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_rq_list_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_tags = {
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.attr = {.name = "tags", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_tags_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
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.attr = {.name = "cpu_list", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_cpus_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_poll = {
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.attr = {.name = "io_poll", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_poll_show,
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};
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static struct attribute *default_hw_ctx_attrs[] = {
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&blk_mq_hw_sysfs_queued.attr,
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&blk_mq_hw_sysfs_run.attr,
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&blk_mq_hw_sysfs_dispatched.attr,
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&blk_mq_hw_sysfs_pending.attr,
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&blk_mq_hw_sysfs_tags.attr,
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&blk_mq_hw_sysfs_cpus.attr,
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&blk_mq_hw_sysfs_active.attr,
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&blk_mq_hw_sysfs_poll.attr,
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NULL,
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};
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static const struct sysfs_ops blk_mq_sysfs_ops = {
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.show = blk_mq_sysfs_show,
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.store = blk_mq_sysfs_store,
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};
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static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
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.show = blk_mq_hw_sysfs_show,
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.store = blk_mq_hw_sysfs_store,
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};
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static struct kobj_type blk_mq_ktype = {
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.sysfs_ops = &blk_mq_sysfs_ops,
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.release = blk_mq_sysfs_release,
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};
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static struct kobj_type blk_mq_ctx_ktype = {
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.sysfs_ops = &blk_mq_sysfs_ops,
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.default_attrs = default_ctx_attrs,
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.release = blk_mq_sysfs_release,
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};
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static struct kobj_type blk_mq_hw_ktype = {
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.sysfs_ops = &blk_mq_hw_sysfs_ops,
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.default_attrs = default_hw_ctx_attrs,
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.release = blk_mq_sysfs_release,
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};
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static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
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{
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struct blk_mq_ctx *ctx;
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int i;
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if (!hctx->nr_ctx)
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return;
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hctx_for_each_ctx(hctx, ctx, i)
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kobject_del(&ctx->kobj);
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kobject_del(&hctx->kobj);
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}
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static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
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{
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struct request_queue *q = hctx->queue;
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struct blk_mq_ctx *ctx;
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int i, ret;
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if (!hctx->nr_ctx)
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return 0;
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ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
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if (ret)
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return ret;
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hctx_for_each_ctx(hctx, ctx, i) {
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ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
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if (ret)
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break;
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}
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return ret;
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}
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static void __blk_mq_unregister_disk(struct gendisk *disk)
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{
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struct request_queue *q = disk->queue;
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struct blk_mq_hw_ctx *hctx;
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struct blk_mq_ctx *ctx;
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int i, j;
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queue_for_each_hw_ctx(q, hctx, i) {
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blk_mq_unregister_hctx(hctx);
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hctx_for_each_ctx(hctx, ctx, j)
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kobject_put(&ctx->kobj);
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kobject_put(&hctx->kobj);
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}
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kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
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kobject_del(&q->mq_kobj);
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kobject_put(&q->mq_kobj);
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kobject_put(&disk_to_dev(disk)->kobj);
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q->mq_sysfs_init_done = false;
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}
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void blk_mq_unregister_disk(struct gendisk *disk)
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{
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blk_mq_disable_hotplug();
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__blk_mq_unregister_disk(disk);
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blk_mq_enable_hotplug();
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}
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void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
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{
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kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
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}
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static void blk_mq_sysfs_init(struct request_queue *q)
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{
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struct blk_mq_ctx *ctx;
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int cpu;
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kobject_init(&q->mq_kobj, &blk_mq_ktype);
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for_each_possible_cpu(cpu) {
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ctx = per_cpu_ptr(q->queue_ctx, cpu);
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kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
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}
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}
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int blk_mq_register_disk(struct gendisk *disk)
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{
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struct device *dev = disk_to_dev(disk);
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struct request_queue *q = disk->queue;
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struct blk_mq_hw_ctx *hctx;
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int ret, i;
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blk_mq_disable_hotplug();
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blk_mq_sysfs_init(q);
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ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
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if (ret < 0)
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goto out;
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kobject_uevent(&q->mq_kobj, KOBJ_ADD);
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queue_for_each_hw_ctx(q, hctx, i) {
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ret = blk_mq_register_hctx(hctx);
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if (ret)
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break;
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}
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if (ret)
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__blk_mq_unregister_disk(disk);
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else
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q->mq_sysfs_init_done = true;
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out:
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blk_mq_enable_hotplug();
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return ret;
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}
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EXPORT_SYMBOL_GPL(blk_mq_register_disk);
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void blk_mq_sysfs_unregister(struct request_queue *q)
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{
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struct blk_mq_hw_ctx *hctx;
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int i;
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if (!q->mq_sysfs_init_done)
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return;
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queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_unregister_hctx(hctx);
|
|
}
|
|
|
|
int blk_mq_sysfs_register(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i, ret = 0;
|
|
|
|
if (!q->mq_sysfs_init_done)
|
|
return ret;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
ret = blk_mq_register_hctx(hctx);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|