block: untangle request_queue refcounting from sysfs

The kobject embedded into the request_queue is used for the queue
directory in sysfs, but that is a child of the gendisks directory and is
intimately tied to it.  Move this kobject to the gendisk and use a
refcount_t in the request_queue for the actual request_queue refcounting
that is completely unrelated to the device model.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221114042637.1009333-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2022-11-14 05:26:36 +01:00 committed by Jens Axboe
parent 40602997be
commit 2bd85221a6
8 changed files with 71 additions and 87 deletions

View File

@ -59,12 +59,12 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
DEFINE_IDA(blk_queue_ida);
static DEFINE_IDA(blk_queue_ida);
/*
* For queue allocation
*/
struct kmem_cache *blk_requestq_cachep;
static struct kmem_cache *blk_requestq_cachep;
/*
* Controlling structure to kblockd
@ -252,19 +252,46 @@ void blk_clear_pm_only(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_clear_pm_only);
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
kmem_cache_free(blk_requestq_cachep,
container_of(rcu_head, struct request_queue, rcu_head));
}
static void blk_free_queue(struct request_queue *q)
{
might_sleep();
percpu_ref_exit(&q->q_usage_counter);
if (q->poll_stat)
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
blk_free_queue_stats(q->stats);
kfree(q->poll_stat);
if (queue_is_mq(q))
blk_mq_release(q);
ida_free(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
/**
* blk_put_queue - decrement the request_queue refcount
* @q: the request_queue structure to decrement the refcount for
*
* Decrements the refcount of the request_queue kobject. When this reaches 0
* we'll have blk_release_queue() called.
* Decrements the refcount of the request_queue and free it when the refcount
* reaches 0.
*
* Context: Any context, but the last reference must not be dropped from
* atomic context.
*/
void blk_put_queue(struct request_queue *q)
{
kobject_put(&q->kobj);
if (refcount_dec_and_test(&q->refs))
blk_free_queue(q);
}
EXPORT_SYMBOL(blk_put_queue);
@ -399,8 +426,7 @@ struct request_queue *blk_alloc_queue(int node_id)
INIT_WORK(&q->timeout_work, blk_timeout_work);
INIT_LIST_HEAD(&q->icq_list);
kobject_init(&q->kobj, &blk_queue_ktype);
refcount_set(&q->refs, 1);
mutex_init(&q->debugfs_mutex);
mutex_init(&q->sysfs_lock);
mutex_init(&q->sysfs_dir_lock);
@ -445,7 +471,7 @@ bool blk_get_queue(struct request_queue *q)
{
if (unlikely(blk_queue_dying(q)))
return false;
kobject_get(&q->kobj);
refcount_inc(&q->refs);
return true;
}
EXPORT_SYMBOL(blk_get_queue);

View File

@ -140,8 +140,8 @@ int blk_crypto_sysfs_register(struct gendisk *disk)
return -ENOMEM;
obj->profile = q->crypto_profile;
err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype, &q->kobj,
"crypto");
err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype,
&disk->queue_kobj, "crypto");
if (err) {
kobject_put(&obj->kobj);
return err;

View File

@ -123,7 +123,8 @@ int disk_register_independent_access_ranges(struct gendisk *disk)
*/
WARN_ON(iars->sysfs_registered);
ret = kobject_init_and_add(&iars->kobj, &blk_ia_ranges_ktype,
&q->kobj, "%s", "independent_access_ranges");
&disk->queue_kobj, "%s",
"independent_access_ranges");
if (ret) {
disk->ia_ranges = NULL;
kobject_put(&iars->kobj);

View File

@ -683,8 +683,8 @@ static struct attribute *queue_attrs[] = {
static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
int n)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
struct request_queue *q = disk->queue;
if (attr == &queue_io_timeout_entry.attr &&
(!q->mq_ops || !q->mq_ops->timeout))
@ -710,8 +710,8 @@ static ssize_t
queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
struct request_queue *q = disk->queue;
ssize_t res;
if (!entry->show)
@ -727,63 +727,19 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
const char *page, size_t length)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q;
struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj);
struct request_queue *q = disk->queue;
ssize_t res;
if (!entry->store)
return -EIO;
q = container_of(kobj, struct request_queue, kobj);
mutex_lock(&q->sysfs_lock);
res = entry->store(q, page, length);
mutex_unlock(&q->sysfs_lock);
return res;
}
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
kmem_cache_free(blk_requestq_cachep,
container_of(rcu_head, struct request_queue, rcu_head));
}
/**
* blk_release_queue - releases all allocated resources of the request_queue
* @kobj: pointer to a kobject, whose container is a request_queue
*
* This function releases all allocated resources of the request queue.
*
* The struct request_queue refcount is incremented with blk_get_queue() and
* decremented with blk_put_queue(). Once the refcount reaches 0 this function
* is called.
*
* Drivers exist which depend on the release of the request_queue to be
* synchronous, it should not be deferred.
*
* Context: can sleep
*/
static void blk_release_queue(struct kobject *kobj)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
might_sleep();
percpu_ref_exit(&q->q_usage_counter);
if (q->poll_stat)
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);
blk_free_queue_stats(q->stats);
kfree(q->poll_stat);
if (queue_is_mq(q))
blk_mq_release(q);
ida_free(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
static const struct sysfs_ops queue_sysfs_ops = {
.show = queue_attr_show,
.store = queue_attr_store,
@ -794,10 +750,15 @@ static const struct attribute_group *blk_queue_attr_groups[] = {
NULL
};
struct kobj_type blk_queue_ktype = {
static void blk_queue_release(struct kobject *kobj)
{
/* nothing to do here, all data is associated with the parent gendisk */
}
static struct kobj_type blk_queue_ktype = {
.default_groups = blk_queue_attr_groups,
.sysfs_ops = &queue_sysfs_ops,
.release = blk_release_queue,
.release = blk_queue_release,
};
static void blk_debugfs_remove(struct gendisk *disk)
@ -823,20 +784,20 @@ int blk_register_queue(struct gendisk *disk)
int ret;
mutex_lock(&q->sysfs_dir_lock);
ret = kobject_add(&q->kobj, &disk_to_dev(disk)->kobj, "queue");
kobject_init(&disk->queue_kobj, &blk_queue_ktype);
ret = kobject_add(&disk->queue_kobj, &disk_to_dev(disk)->kobj, "queue");
if (ret < 0)
goto out_unlock_dir;
goto out_put_queue_kobj;
if (queue_is_mq(q)) {
ret = blk_mq_sysfs_register(disk);
if (ret)
goto out_del_queue_kobj;
goto out_put_queue_kobj;
}
mutex_lock(&q->sysfs_lock);
mutex_lock(&q->debugfs_mutex);
q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
blk_debugfs_root);
q->debugfs_dir = debugfs_create_dir(disk->disk_name, blk_debugfs_root);
if (queue_is_mq(q))
blk_mq_debugfs_register(q);
mutex_unlock(&q->debugfs_mutex);
@ -860,7 +821,7 @@ int blk_register_queue(struct gendisk *disk)
blk_throtl_register(disk);
/* Now everything is ready and send out KOBJ_ADD uevent */
kobject_uevent(&q->kobj, KOBJ_ADD);
kobject_uevent(&disk->queue_kobj, KOBJ_ADD);
if (q->elevator)
kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
mutex_unlock(&q->sysfs_lock);
@ -889,9 +850,8 @@ out_unregister_ia_ranges:
out_debugfs_remove:
blk_debugfs_remove(disk);
mutex_unlock(&q->sysfs_lock);
out_del_queue_kobj:
kobject_del(&q->kobj);
out_unlock_dir:
out_put_queue_kobj:
kobject_put(&disk->queue_kobj);
mutex_unlock(&q->sysfs_dir_lock);
return ret;
}
@ -938,8 +898,8 @@ void blk_unregister_queue(struct gendisk *disk)
mutex_unlock(&q->sysfs_lock);
/* Now that we've deleted all child objects, we can delete the queue. */
kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
kobject_uevent(&disk->queue_kobj, KOBJ_REMOVE);
kobject_del(&disk->queue_kobj);
mutex_unlock(&q->sysfs_dir_lock);
blk_debugfs_remove(disk);

View File

@ -26,10 +26,6 @@ struct blk_flush_queue {
spinlock_t mq_flush_lock;
};
extern struct kmem_cache *blk_requestq_cachep;
extern struct kobj_type blk_queue_ktype;
extern struct ida blk_queue_ida;
bool is_flush_rq(struct request *req);
struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,

View File

@ -175,8 +175,10 @@ static void bsg_device_release(struct device *dev)
void bsg_unregister_queue(struct bsg_device *bd)
{
if (bd->queue->kobj.sd)
sysfs_remove_link(&bd->queue->kobj, "bsg");
struct gendisk *disk = bd->queue->disk;
if (disk && disk->queue_kobj.sd)
sysfs_remove_link(&disk->queue_kobj, "bsg");
cdev_device_del(&bd->cdev, &bd->device);
put_device(&bd->device);
}
@ -216,8 +218,9 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
if (ret)
goto out_put_device;
if (q->kobj.sd) {
ret = sysfs_create_link(&q->kobj, &bd->device.kobj, "bsg");
if (q->disk && q->disk->queue_kobj.sd) {
ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj,
"bsg");
if (ret)
goto out_device_del;
}

View File

@ -467,7 +467,7 @@ int elv_register_queue(struct request_queue *q, bool uevent)
lockdep_assert_held(&q->sysfs_lock);
error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
error = kobject_add(&e->kobj, &q->disk->queue_kobj, "iosched");
if (!error) {
struct elv_fs_entry *attr = e->type->elevator_attrs;
if (attr) {

View File

@ -155,6 +155,7 @@ struct gendisk {
unsigned open_partitions; /* number of open partitions */
struct backing_dev_info *bdi;
struct kobject queue_kobj; /* the queue/ directory */
struct kobject *slave_dir;
#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
struct list_head slave_bdevs;
@ -430,10 +431,7 @@ struct request_queue {
struct gendisk *disk;
/*
* queue kobject
*/
struct kobject kobj;
refcount_t refs;
/*
* mq queue kobject