[deliverable/linux.git] / block / blk-sysfs.c

/*
 * Functions related to sysfs handling
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/blktrace_api.h>
#include <linux/blk-mq.h>
#include <linux/blk-cgroup.h>

#include "blk.h"
#include "blk-mq.h"

struct queue_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct request_queue *, char *);
	ssize_t (*store)(struct request_queue *, const char *, size_t);
};

static ssize_t
queue_var_show(unsigned long var, char *page)
{
	return sprintf(page, "%lu\n", var);
}

static ssize_t
queue_var_store(unsigned long *var, const char *page, size_t count)
{
	int err;
	unsigned long v;

	err = kstrtoul(page, 10, &v);
	if (err || v > UINT_MAX)
		return -EINVAL;

	*var = v;

	return count;
}

static ssize_t queue_requests_show(struct request_queue *q, char *page)
{
	return queue_var_show(q->nr_requests, (page));
}

static ssize_t
queue_requests_store(struct request_queue *q, const char *page, size_t count)
{
	unsigned long nr;
	int ret, err;

	if (!q->request_fn && !q->mq_ops)
		return -EINVAL;

	ret = queue_var_store(&nr, page, count);
	if (ret < 0)
		return ret;

	if (nr < BLKDEV_MIN_RQ)
		nr = BLKDEV_MIN_RQ;

	if (q->request_fn)
		err = blk_update_nr_requests(q, nr);
	else
		err = blk_mq_update_nr_requests(q, nr);

	if (err)
		return err;

	return ret;
}

static ssize_t queue_ra_show(struct request_queue *q, char *page)
{
	unsigned long ra_kb = q->backing_dev_info.ra_pages <<
					(PAGE_CACHE_SHIFT - 10);

	return queue_var_show(ra_kb, (page));
}

static ssize_t
queue_ra_store(struct request_queue *q, const char *page, size_t count)
{
	unsigned long ra_kb;
	ssize_t ret = queue_var_store(&ra_kb, page, count);

	if (ret < 0)
		return ret;

	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);

	return ret;
}

static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
{
	int max_sectors_kb = queue_max_sectors(q) >> 1;

	return queue_var_show(max_sectors_kb, (page));
}

static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_max_segments(q), (page));
}

static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
{
	return queue_var_show(q->limits.max_integrity_segments, (page));
}

static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
	if (blk_queue_cluster(q))
		return queue_var_show(queue_max_segment_size(q), (page));

	return queue_var_show(PAGE_CACHE_SIZE, (page));
}

static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_logical_block_size(q), page);
}

static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_physical_block_size(q), page);
}

static ssize_t queue_io_min_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_io_min(q), page);
}

static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_io_opt(q), page);
}

static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
{
	return queue_var_show(q->limits.discard_granularity, page);
}

static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
{
	return sprintf(page, "%llu\n",
		       (unsigned long long)q->limits.max_discard_sectors << 9);
}

static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
{
	return queue_var_show(queue_discard_zeroes_data(q), page);
}

static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
{
	return sprintf(page, "%llu\n",
		(unsigned long long)q->limits.max_write_same_sectors << 9);
}


static ssize_t
queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
{
	unsigned long max_sectors_kb,
		max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);

	if (ret < 0)
		return ret;

	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
		return -EINVAL;

	spin_lock_irq(q->queue_lock);
	q->limits.max_sectors = max_sectors_kb << 1;
	spin_unlock_irq(q->queue_lock);

	return ret;
}

static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
{
	int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;

	return queue_var_show(max_hw_sectors_kb, (page));
}

#define QUEUE_SYSFS_BIT_FNS(name, flag, neg)				\
static ssize_t								\
queue_show_##name(struct request_queue *q, char *page)			\
{									\
	int bit;							\
	bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);		\
	return queue_var_show(neg ? !bit : bit, page);			\
}									\
static ssize_t								\
queue_store_##name(struct request_queue *q, const char *page, size_t count) \
{									\
	unsigned long val;						\
	ssize_t ret;							\
	ret = queue_var_store(&val, page, count);			\
	if (ret < 0)							\
		 return ret;						\
	if (neg)							\
		val = !val;						\
									\
	spin_lock_irq(q->queue_lock);					\
	if (val)							\
		queue_flag_set(QUEUE_FLAG_##flag, q);			\
	else								\
		queue_flag_clear(QUEUE_FLAG_##flag, q);			\
	spin_unlock_irq(q->queue_lock);					\
	return ret;							\
}

QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
#undef QUEUE_SYSFS_BIT_FNS

static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
{
	return queue_var_show((blk_queue_nomerges(q) << 1) |
			       blk_queue_noxmerges(q), page);
}

static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
				    size_t count)
{
	unsigned long nm;
	ssize_t ret = queue_var_store(&nm, page, count);

	if (ret < 0)
		return ret;

	spin_lock_irq(q->queue_lock);
	queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
	queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
	if (nm == 2)
		queue_flag_set(QUEUE_FLAG_NOMERGES, q);
	else if (nm)
		queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
	spin_unlock_irq(q->queue_lock);

	return ret;
}

static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
{
	bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
	bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);

	return queue_var_show(set << force, page);
}

static ssize_t
queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
{
	ssize_t ret = -EINVAL;
#ifdef CONFIG_SMP
	unsigned long val;

	ret = queue_var_store(&val, page, count);
	if (ret < 0)
		return ret;

	spin_lock_irq(q->queue_lock);
	if (val == 2) {
		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
		queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
	} else if (val == 1) {
		queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
	} else if (val == 0) {
		queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
		queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
	}
	spin_unlock_irq(q->queue_lock);
#endif
	return ret;
}

static struct queue_sysfs_entry queue_requests_entry = {
	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
	.show = queue_requests_show,
	.store = queue_requests_store,
};

static struct queue_sysfs_entry queue_ra_entry = {
	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
	.show = queue_ra_show,
	.store = queue_ra_store,
};

static struct queue_sysfs_entry queue_max_sectors_entry = {
	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
	.show = queue_max_sectors_show,
	.store = queue_max_sectors_store,
};

static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
	.show = queue_max_hw_sectors_show,
};

static struct queue_sysfs_entry queue_max_segments_entry = {
	.attr = {.name = "max_segments", .mode = S_IRUGO },
	.show = queue_max_segments_show,
};

static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
	.show = queue_max_integrity_segments_show,
};

static struct queue_sysfs_entry queue_max_segment_size_entry = {
	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
	.show = queue_max_segment_size_show,
};

static struct queue_sysfs_entry queue_iosched_entry = {
	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
	.show = elv_iosched_show,
	.store = elv_iosched_store,
};

static struct queue_sysfs_entry queue_hw_sector_size_entry = {
	.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
	.show = queue_logical_block_size_show,
};

static struct queue_sysfs_entry queue_logical_block_size_entry = {
	.attr = {.name = "logical_block_size", .mode = S_IRUGO },
	.show = queue_logical_block_size_show,
};

static struct queue_sysfs_entry queue_physical_block_size_entry = {
	.attr = {.name = "physical_block_size", .mode = S_IRUGO },
	.show = queue_physical_block_size_show,
};

static struct queue_sysfs_entry queue_io_min_entry = {
	.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
	.show = queue_io_min_show,
};

static struct queue_sysfs_entry queue_io_opt_entry = {
	.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
	.show = queue_io_opt_show,
};

static struct queue_sysfs_entry queue_discard_granularity_entry = {
	.attr = {.name = "discard_granularity", .mode = S_IRUGO },
	.show = queue_discard_granularity_show,
};

static struct queue_sysfs_entry queue_discard_max_entry = {
	.attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
	.show = queue_discard_max_show,
};

static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
	.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
	.show = queue_discard_zeroes_data_show,
};

static struct queue_sysfs_entry queue_write_same_max_entry = {
	.attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
	.show = queue_write_same_max_show,
};

static struct queue_sysfs_entry queue_nonrot_entry = {
	.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
	.show = queue_show_nonrot,
	.store = queue_store_nonrot,
};

static struct queue_sysfs_entry queue_nomerges_entry = {
	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
	.show = queue_nomerges_show,
	.store = queue_nomerges_store,
};

static struct queue_sysfs_entry queue_rq_affinity_entry = {
	.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
	.show = queue_rq_affinity_show,
	.store = queue_rq_affinity_store,
};

static struct queue_sysfs_entry queue_iostats_entry = {
	.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
	.show = queue_show_iostats,
	.store = queue_store_iostats,
};

static struct queue_sysfs_entry queue_random_entry = {
	.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
	.show = queue_show_random,
	.store = queue_store_random,
};

static struct attribute *default_attrs[] = {
	&queue_requests_entry.attr,
	&queue_ra_entry.attr,
	&queue_max_hw_sectors_entry.attr,
	&queue_max_sectors_entry.attr,
	&queue_max_segments_entry.attr,
	&queue_max_integrity_segments_entry.attr,
	&queue_max_segment_size_entry.attr,
	&queue_iosched_entry.attr,
	&queue_hw_sector_size_entry.attr,
	&queue_logical_block_size_entry.attr,
	&queue_physical_block_size_entry.attr,
	&queue_io_min_entry.attr,
	&queue_io_opt_entry.attr,
	&queue_discard_granularity_entry.attr,
	&queue_discard_max_entry.attr,
	&queue_discard_zeroes_data_entry.attr,
	&queue_write_same_max_entry.attr,
	&queue_nonrot_entry.attr,
	&queue_nomerges_entry.attr,
	&queue_rq_affinity_entry.attr,
	&queue_iostats_entry.attr,
	&queue_random_entry.attr,
	NULL,
};

#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)

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);
	ssize_t res;

	if (!entry->show)
		return -EIO;
	mutex_lock(&q->sysfs_lock);
	if (blk_queue_dying(q)) {
		mutex_unlock(&q->sysfs_lock);
		return -ENOENT;
	}
	res = entry->show(q, page);
	mutex_unlock(&q->sysfs_lock);
	return res;
}

static ssize_t
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;
	ssize_t res;

	if (!entry->store)
		return -EIO;

	q = container_of(kobj, struct request_queue, kobj);
	mutex_lock(&q->sysfs_lock);
	if (blk_queue_dying(q)) {
		mutex_unlock(&q->sysfs_lock);
		return -ENOENT;
	}
	res = entry->store(q, page, length);
	mutex_unlock(&q->sysfs_lock);
	return res;
}

static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
	struct request_queue *q = container_of(rcu_head, struct request_queue,
					       rcu_head);
	kmem_cache_free(blk_requestq_cachep, q);
}

/**
 * blk_release_queue: - release a &struct request_queue when it is no longer needed
 * @kobj:    the kobj belonging to the request queue to be released
 *
 * Description:
 *     blk_release_queue is the pair to blk_init_queue() or
 *     blk_queue_make_request().  It should be called when a request queue is
 *     being released; typically when a block device is being de-registered.
 *     Currently, its primary task it to free all the &struct request
 *     structures that were allocated to the queue and the queue itself.
 *
 * Note:
 *     The low level driver must have finished any outstanding requests first
 *     via blk_cleanup_queue().
 **/
static void blk_release_queue(struct kobject *kobj)
{
	struct request_queue *q =
		container_of(kobj, struct request_queue, kobj);

	blkcg_exit_queue(q);

	if (q->elevator) {
		spin_lock_irq(q->queue_lock);
		ioc_clear_queue(q);
		spin_unlock_irq(q->queue_lock);
		elevator_exit(q->elevator);
	}

	blk_exit_rl(&q->root_rl);

	if (q->queue_tags)
		__blk_queue_free_tags(q);

	if (!q->mq_ops)
		blk_free_flush_queue(q->fq);
	else
		blk_mq_release(q);

	blk_trace_shutdown(q);

	ida_simple_remove(&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,
};

struct kobj_type blk_queue_ktype = {
	.sysfs_ops	= &queue_sysfs_ops,
	.default_attrs	= default_attrs,
	.release	= blk_release_queue,
};

int blk_register_queue(struct gendisk *disk)
{
	int ret;
	struct device *dev = disk_to_dev(disk);
	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return -ENXIO;

	/*
	 * SCSI probing may synchronously create and destroy a lot of
	 * request_queues for non-existent devices.  Shutting down a fully
	 * functional queue takes measureable wallclock time as RCU grace
	 * periods are involved.  To avoid excessive latency in these
	 * cases, a request_queue starts out in a degraded mode which is
	 * faster to shut down and is made fully functional here as
	 * request_queues for non-existent devices never get registered.
	 */
	if (!blk_queue_init_done(q)) {
		queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
		blk_queue_bypass_end(q);
		if (q->mq_ops)
			blk_mq_finish_init(q);
	}

	ret = blk_trace_init_sysfs(dev);
	if (ret)
		return ret;

	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
	if (ret < 0) {
		blk_trace_remove_sysfs(dev);
		return ret;
	}

	kobject_uevent(&q->kobj, KOBJ_ADD);

	if (q->mq_ops)
		blk_mq_register_disk(disk);

	if (!q->request_fn)
		return 0;

	ret = elv_register_queue(q);
	if (ret) {
		kobject_uevent(&q->kobj, KOBJ_REMOVE);
		kobject_del(&q->kobj);
		blk_trace_remove_sysfs(dev);
		kobject_put(&dev->kobj);
		return ret;
	}

	return 0;
}

void blk_unregister_queue(struct gendisk *disk)
{
	struct request_queue *q = disk->queue;

	if (WARN_ON(!q))
		return;

	if (q->mq_ops)
		blk_mq_unregister_disk(disk);

	if (q->request_fn)
		elv_unregister_queue(q);

	kobject_uevent(&q->kobj, KOBJ_REMOVE);
	kobject_del(&q->kobj);
	blk_trace_remove_sysfs(disk_to_dev(disk));
	kobject_put(&disk_to_dev(disk)->kobj);
}
Commit	Line	Data
	1	/*
	2	* Functions related to sysfs handling
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/slab.h>
	6	#include <linux/module.h>
	7	#include <linux/bio.h>
	8	#include <linux/blkdev.h>
	9	#include <linux/backing-dev.h>
	10	#include <linux/blktrace_api.h>
	11	#include <linux/blk-mq.h>
	12	#include <linux/blk-cgroup.h>
	13
	14	#include "blk.h"
	15	#include "blk-mq.h"
	16
	17	struct queue_sysfs_entry {
	18	struct attribute attr;
	19	ssize_t (show)(struct request_queue , char *);
	20	ssize_t (store)(struct request_queue , const char *, size_t);
	21	};
	22
	23	static ssize_t
	24	queue_var_show(unsigned long var, char *page)
	25	{
	26	return sprintf(page, "%lu\n", var);
	27	}
	28
	29	static ssize_t
	30	queue_var_store(unsigned long var, const char page, size_t count)
	31	{
	32	int err;
	33	unsigned long v;
	34
	35	err = kstrtoul(page, 10, &v);
	36	if (err \|\| v > UINT_MAX)
	37	return -EINVAL;
	38
	39	*var = v;
	40
	41	return count;
	42	}
	43
	44	static ssize_t queue_requests_show(struct request_queue q, char page)
	45	{
	46	return queue_var_show(q->nr_requests, (page));
	47	}
	48
	49	static ssize_t
	50	queue_requests_store(struct request_queue q, const char page, size_t count)
	51	{
	52	unsigned long nr;
	53	int ret, err;
	54
	55	if (!q->request_fn && !q->mq_ops)
	56	return -EINVAL;
	57
	58	ret = queue_var_store(&nr, page, count);
	59	if (ret < 0)
	60	return ret;
	61
	62	if (nr < BLKDEV_MIN_RQ)
	63	nr = BLKDEV_MIN_RQ;
	64
	65	if (q->request_fn)
	66	err = blk_update_nr_requests(q, nr);
	67	else
	68	err = blk_mq_update_nr_requests(q, nr);
	69
	70	if (err)
	71	return err;
	72
	73	return ret;
	74	}
	75
	76	static ssize_t queue_ra_show(struct request_queue q, char page)
	77	{
	78	unsigned long ra_kb = q->backing_dev_info.ra_pages <<
	79	(PAGE_CACHE_SHIFT - 10);
	80
	81	return queue_var_show(ra_kb, (page));
	82	}
	83
	84	static ssize_t
	85	queue_ra_store(struct request_queue q, const char page, size_t count)
	86	{
	87	unsigned long ra_kb;
	88	ssize_t ret = queue_var_store(&ra_kb, page, count);
	89
	90	if (ret < 0)
	91	return ret;
	92
	93	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
	94
	95	return ret;
	96	}
	97
	98	static ssize_t queue_max_sectors_show(struct request_queue q, char page)
	99	{
	100	int max_sectors_kb = queue_max_sectors(q) >> 1;
	101
	102	return queue_var_show(max_sectors_kb, (page));
	103	}
	104
	105	static ssize_t queue_max_segments_show(struct request_queue q, char page)
	106	{
	107	return queue_var_show(queue_max_segments(q), (page));
	108	}
	109
	110	static ssize_t queue_max_integrity_segments_show(struct request_queue q, char page)
	111	{
	112	return queue_var_show(q->limits.max_integrity_segments, (page));
	113	}
	114
	115	static ssize_t queue_max_segment_size_show(struct request_queue q, char page)
	116	{
	117	if (blk_queue_cluster(q))
	118	return queue_var_show(queue_max_segment_size(q), (page));
	119
	120	return queue_var_show(PAGE_CACHE_SIZE, (page));
	121	}
	122
	123	static ssize_t queue_logical_block_size_show(struct request_queue q, char page)
	124	{
	125	return queue_var_show(queue_logical_block_size(q), page);
	126	}
	127
	128	static ssize_t queue_physical_block_size_show(struct request_queue q, char page)
	129	{
	130	return queue_var_show(queue_physical_block_size(q), page);
	131	}
	132
	133	static ssize_t queue_io_min_show(struct request_queue q, char page)
	134	{
	135	return queue_var_show(queue_io_min(q), page);
	136	}
	137
	138	static ssize_t queue_io_opt_show(struct request_queue q, char page)
	139	{
	140	return queue_var_show(queue_io_opt(q), page);
	141	}
	142
	143	static ssize_t queue_discard_granularity_show(struct request_queue q, char page)
	144	{
	145	return queue_var_show(q->limits.discard_granularity, page);
	146	}
	147
	148	static ssize_t queue_discard_max_show(struct request_queue q, char page)
	149	{
	150	return sprintf(page, "%llu\n",
	151	(unsigned long long)q->limits.max_discard_sectors << 9);
	152	}
	153
	154	static ssize_t queue_discard_zeroes_data_show(struct request_queue q, char page)
	155	{
	156	return queue_var_show(queue_discard_zeroes_data(q), page);
	157	}
	158
	159	static ssize_t queue_write_same_max_show(struct request_queue q, char page)
	160	{
	161	return sprintf(page, "%llu\n",
	162	(unsigned long long)q->limits.max_write_same_sectors << 9);
	163	}
	164
	165
	166	static ssize_t
	167	queue_max_sectors_store(struct request_queue q, const char page, size_t count)
	168	{
	169	unsigned long max_sectors_kb,
	170	max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
	171	page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
	172	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
	173
	174	if (ret < 0)
	175	return ret;
	176
	177	if (max_sectors_kb > max_hw_sectors_kb \|\| max_sectors_kb < page_kb)
	178	return -EINVAL;
	179
	180	spin_lock_irq(q->queue_lock);
	181	q->limits.max_sectors = max_sectors_kb << 1;
	182	spin_unlock_irq(q->queue_lock);
	183
	184	return ret;
	185	}
	186
	187	static ssize_t queue_max_hw_sectors_show(struct request_queue q, char page)
	188	{
	189	int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
	190
	191	return queue_var_show(max_hw_sectors_kb, (page));
	192	}
	193
	194	#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
	195	static ssize_t \
	196	queue_show_##name(struct request_queue q, char page) \
	197	{ \
	198	int bit; \
	199	bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
	200	return queue_var_show(neg ? !bit : bit, page); \
	201	} \
	202	static ssize_t \
	203	queue_store_##name(struct request_queue q, const char page, size_t count) \
	204	{ \
	205	unsigned long val; \
	206	ssize_t ret; \
	207	ret = queue_var_store(&val, page, count); \
	208	if (ret < 0) \
	209	return ret; \
	210	if (neg) \
	211	val = !val; \
	212	\
	213	spin_lock_irq(q->queue_lock); \
	214	if (val) \
	215	queue_flag_set(QUEUE_FLAG_##flag, q); \
	216	else \
	217	queue_flag_clear(QUEUE_FLAG_##flag, q); \
	218	spin_unlock_irq(q->queue_lock); \
	219	return ret; \
	220	}
	221
	222	QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
	223	QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
	224	QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
	225	#undef QUEUE_SYSFS_BIT_FNS
	226
	227	static ssize_t queue_nomerges_show(struct request_queue q, char page)
	228	{
	229	return queue_var_show((blk_queue_nomerges(q) << 1) \|
	230	blk_queue_noxmerges(q), page);
	231	}
	232
	233	static ssize_t queue_nomerges_store(struct request_queue q, const char page,
	234	size_t count)
	235	{
	236	unsigned long nm;
	237	ssize_t ret = queue_var_store(&nm, page, count);
	238
	239	if (ret < 0)
	240	return ret;
	241
	242	spin_lock_irq(q->queue_lock);
	243	queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
	244	queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
	245	if (nm == 2)
	246	queue_flag_set(QUEUE_FLAG_NOMERGES, q);
	247	else if (nm)
	248	queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
	249	spin_unlock_irq(q->queue_lock);
	250
	251	return ret;
	252	}
	253
	254	static ssize_t queue_rq_affinity_show(struct request_queue q, char page)
	255	{
	256	bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
	257	bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
	258
	259	return queue_var_show(set << force, page);
	260	}
	261
	262	static ssize_t
	263	queue_rq_affinity_store(struct request_queue q, const char page, size_t count)
	264	{
	265	ssize_t ret = -EINVAL;
	266	#ifdef CONFIG_SMP
	267	unsigned long val;
	268
	269	ret = queue_var_store(&val, page, count);
	270	if (ret < 0)
	271	return ret;
	272
	273	spin_lock_irq(q->queue_lock);
	274	if (val == 2) {
	275	queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
	276	queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
	277	} else if (val == 1) {
	278	queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
	279	queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
	280	} else if (val == 0) {
	281	queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
	282	queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
	283	}
	284	spin_unlock_irq(q->queue_lock);
	285	#endif
	286	return ret;
	287	}
	288
	289	static struct queue_sysfs_entry queue_requests_entry = {
	290	.attr = {.name = "nr_requests", .mode = S_IRUGO \| S_IWUSR },
	291	.show = queue_requests_show,
	292	.store = queue_requests_store,
	293	};
	294
	295	static struct queue_sysfs_entry queue_ra_entry = {
	296	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO \| S_IWUSR },
	297	.show = queue_ra_show,
	298	.store = queue_ra_store,
	299	};
	300
	301	static struct queue_sysfs_entry queue_max_sectors_entry = {
	302	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO \| S_IWUSR },
	303	.show = queue_max_sectors_show,
	304	.store = queue_max_sectors_store,
	305	};
	306
	307	static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
	308	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
	309	.show = queue_max_hw_sectors_show,
	310	};
	311
	312	static struct queue_sysfs_entry queue_max_segments_entry = {
	313	.attr = {.name = "max_segments", .mode = S_IRUGO },
	314	.show = queue_max_segments_show,
	315	};
	316
	317	static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
	318	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
	319	.show = queue_max_integrity_segments_show,
	320	};
	321
	322	static struct queue_sysfs_entry queue_max_segment_size_entry = {
	323	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
	324	.show = queue_max_segment_size_show,
	325	};
	326
	327	static struct queue_sysfs_entry queue_iosched_entry = {
	328	.attr = {.name = "scheduler", .mode = S_IRUGO \| S_IWUSR },
	329	.show = elv_iosched_show,
	330	.store = elv_iosched_store,
	331	};
	332
	333	static struct queue_sysfs_entry queue_hw_sector_size_entry = {
	334	.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
	335	.show = queue_logical_block_size_show,
	336	};
	337
	338	static struct queue_sysfs_entry queue_logical_block_size_entry = {
	339	.attr = {.name = "logical_block_size", .mode = S_IRUGO },
	340	.show = queue_logical_block_size_show,
	341	};
	342
	343	static struct queue_sysfs_entry queue_physical_block_size_entry = {
	344	.attr = {.name = "physical_block_size", .mode = S_IRUGO },
	345	.show = queue_physical_block_size_show,
	346	};
	347
	348	static struct queue_sysfs_entry queue_io_min_entry = {
	349	.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
	350	.show = queue_io_min_show,
	351	};
	352
	353	static struct queue_sysfs_entry queue_io_opt_entry = {
	354	.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
	355	.show = queue_io_opt_show,
	356	};
	357
	358	static struct queue_sysfs_entry queue_discard_granularity_entry = {
	359	.attr = {.name = "discard_granularity", .mode = S_IRUGO },
	360	.show = queue_discard_granularity_show,
	361	};
	362
	363	static struct queue_sysfs_entry queue_discard_max_entry = {
	364	.attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
	365	.show = queue_discard_max_show,
	366	};
	367
	368	static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
	369	.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
	370	.show = queue_discard_zeroes_data_show,
	371	};
	372
	373	static struct queue_sysfs_entry queue_write_same_max_entry = {
	374	.attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
	375	.show = queue_write_same_max_show,
	376	};
	377
	378	static struct queue_sysfs_entry queue_nonrot_entry = {
	379	.attr = {.name = "rotational", .mode = S_IRUGO \| S_IWUSR },
	380	.show = queue_show_nonrot,
	381	.store = queue_store_nonrot,
	382	};
	383
	384	static struct queue_sysfs_entry queue_nomerges_entry = {
	385	.attr = {.name = "nomerges", .mode = S_IRUGO \| S_IWUSR },
	386	.show = queue_nomerges_show,
	387	.store = queue_nomerges_store,
	388	};
	389
	390	static struct queue_sysfs_entry queue_rq_affinity_entry = {
	391	.attr = {.name = "rq_affinity", .mode = S_IRUGO \| S_IWUSR },
	392	.show = queue_rq_affinity_show,
	393	.store = queue_rq_affinity_store,
	394	};
	395
	396	static struct queue_sysfs_entry queue_iostats_entry = {
	397	.attr = {.name = "iostats", .mode = S_IRUGO \| S_IWUSR },
	398	.show = queue_show_iostats,
	399	.store = queue_store_iostats,
	400	};
	401
	402	static struct queue_sysfs_entry queue_random_entry = {
	403	.attr = {.name = "add_random", .mode = S_IRUGO \| S_IWUSR },
	404	.show = queue_show_random,
	405	.store = queue_store_random,
	406	};
	407
	408	static struct attribute *default_attrs[] = {
	409	&queue_requests_entry.attr,
	410	&queue_ra_entry.attr,
	411	&queue_max_hw_sectors_entry.attr,
	412	&queue_max_sectors_entry.attr,
	413	&queue_max_segments_entry.attr,
	414	&queue_max_integrity_segments_entry.attr,
	415	&queue_max_segment_size_entry.attr,
	416	&queue_iosched_entry.attr,
	417	&queue_hw_sector_size_entry.attr,
	418	&queue_logical_block_size_entry.attr,
	419	&queue_physical_block_size_entry.attr,
	420	&queue_io_min_entry.attr,
	421	&queue_io_opt_entry.attr,
	422	&queue_discard_granularity_entry.attr,
	423	&queue_discard_max_entry.attr,
	424	&queue_discard_zeroes_data_entry.attr,
	425	&queue_write_same_max_entry.attr,
	426	&queue_nonrot_entry.attr,
	427	&queue_nomerges_entry.attr,
	428	&queue_rq_affinity_entry.attr,
	429	&queue_iostats_entry.attr,
	430	&queue_random_entry.attr,
	431	NULL,
	432	};
	433
	434	#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
	435
	436	static ssize_t
	437	queue_attr_show(struct kobject kobj, struct attribute attr, char *page)
	438	{
	439	struct queue_sysfs_entry *entry = to_queue(attr);
	440	struct request_queue *q =
	441	container_of(kobj, struct request_queue, kobj);
	442	ssize_t res;
	443
	444	if (!entry->show)
	445	return -EIO;
	446	mutex_lock(&q->sysfs_lock);
	447	if (blk_queue_dying(q)) {
	448	mutex_unlock(&q->sysfs_lock);
	449	return -ENOENT;
	450	}
	451	res = entry->show(q, page);
	452	mutex_unlock(&q->sysfs_lock);
	453	return res;
	454	}
	455
	456	static ssize_t
	457	queue_attr_store(struct kobject kobj, struct attribute attr,
	458	const char *page, size_t length)
	459	{
	460	struct queue_sysfs_entry *entry = to_queue(attr);
	461	struct request_queue *q;
	462	ssize_t res;
	463
	464	if (!entry->store)
	465	return -EIO;
	466
	467	q = container_of(kobj, struct request_queue, kobj);
	468	mutex_lock(&q->sysfs_lock);
	469	if (blk_queue_dying(q)) {
	470	mutex_unlock(&q->sysfs_lock);
	471	return -ENOENT;
	472	}
	473	res = entry->store(q, page, length);
	474	mutex_unlock(&q->sysfs_lock);
	475	return res;
	476	}
	477
	478	static void blk_free_queue_rcu(struct rcu_head *rcu_head)
	479	{
	480	struct request_queue *q = container_of(rcu_head, struct request_queue,
	481	rcu_head);
	482	kmem_cache_free(blk_requestq_cachep, q);
	483	}
	484
	485	/**
	486	* blk_release_queue: - release a &struct request_queue when it is no longer needed
	487	* @kobj: the kobj belonging to the request queue to be released
	488	*
	489	* Description:
	490	* blk_release_queue is the pair to blk_init_queue() or
	491	* blk_queue_make_request(). It should be called when a request queue is
	492	* being released; typically when a block device is being de-registered.
	493	* Currently, its primary task it to free all the &struct request
	494	* structures that were allocated to the queue and the queue itself.
	495	*
	496	* Note:
	497	* The low level driver must have finished any outstanding requests first
	498	* via blk_cleanup_queue().
	499	**/
	500	static void blk_release_queue(struct kobject *kobj)
	501	{
	502	struct request_queue *q =
	503	container_of(kobj, struct request_queue, kobj);
	504
	505	blkcg_exit_queue(q);
	506
	507	if (q->elevator) {
	508	spin_lock_irq(q->queue_lock);
	509	ioc_clear_queue(q);
	510	spin_unlock_irq(q->queue_lock);
	511	elevator_exit(q->elevator);
	512	}
	513
	514	blk_exit_rl(&q->root_rl);
	515
	516	if (q->queue_tags)
	517	__blk_queue_free_tags(q);
	518
	519	if (!q->mq_ops)
	520	blk_free_flush_queue(q->fq);
	521	else
	522	blk_mq_release(q);
	523
	524	blk_trace_shutdown(q);
	525
	526	ida_simple_remove(&blk_queue_ida, q->id);
	527	call_rcu(&q->rcu_head, blk_free_queue_rcu);
	528	}
	529
	530	static const struct sysfs_ops queue_sysfs_ops = {
	531	.show = queue_attr_show,
	532	.store = queue_attr_store,
	533	};
	534
	535	struct kobj_type blk_queue_ktype = {
	536	.sysfs_ops = &queue_sysfs_ops,
	537	.default_attrs = default_attrs,
	538	.release = blk_release_queue,
	539	};
	540
	541	int blk_register_queue(struct gendisk *disk)
	542	{
	543	int ret;
	544	struct device *dev = disk_to_dev(disk);
	545	struct request_queue *q = disk->queue;
	546
	547	if (WARN_ON(!q))
	548	return -ENXIO;
	549
	550	/*
	551	* SCSI probing may synchronously create and destroy a lot of
	552	* request_queues for non-existent devices. Shutting down a fully
	553	* functional queue takes measureable wallclock time as RCU grace
	554	* periods are involved. To avoid excessive latency in these
	555	* cases, a request_queue starts out in a degraded mode which is
	556	* faster to shut down and is made fully functional here as
	557	* request_queues for non-existent devices never get registered.
	558	*/
	559	if (!blk_queue_init_done(q)) {
	560	queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
	561	blk_queue_bypass_end(q);
	562	if (q->mq_ops)
	563	blk_mq_finish_init(q);
	564	}
	565
	566	ret = blk_trace_init_sysfs(dev);
	567	if (ret)
	568	return ret;
	569
	570	ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
	571	if (ret < 0) {
	572	blk_trace_remove_sysfs(dev);
	573	return ret;
	574	}
	575
	576	kobject_uevent(&q->kobj, KOBJ_ADD);
	577
	578	if (q->mq_ops)
	579	blk_mq_register_disk(disk);
	580
	581	if (!q->request_fn)
	582	return 0;
	583
	584	ret = elv_register_queue(q);
	585	if (ret) {
	586	kobject_uevent(&q->kobj, KOBJ_REMOVE);
	587	kobject_del(&q->kobj);
	588	blk_trace_remove_sysfs(dev);
	589	kobject_put(&dev->kobj);
	590	return ret;
	591	}
	592
	593	return 0;
	594	}
	595
	596	void blk_unregister_queue(struct gendisk *disk)
	597	{
	598	struct request_queue *q = disk->queue;
	599
	600	if (WARN_ON(!q))
	601	return;
	602
	603	if (q->mq_ops)
	604	blk_mq_unregister_disk(disk);
	605
	606	if (q->request_fn)
	607	elv_unregister_queue(q);
	608
	609	kobject_uevent(&q->kobj, KOBJ_REMOVE);
	610	kobject_del(&q->kobj);
	611	blk_trace_remove_sysfs(disk_to_dev(disk));
	612	kobject_put(&disk_to_dev(disk)->kobj);
	613	}