path: root/block/blk-sysfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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/debugfs.h>

#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
#include "blk-wbt.h"
#include "blk-cgroup.h"
#include "blk-throttle.h"

struct queue_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct gendisk *disk, char *page);
	ssize_t (*show_limit)(struct gendisk *disk, char *page);

	ssize_t (*store)(struct gendisk *disk, const char *page, size_t count);
	int (*store_limit)(struct gendisk *disk, const char *page,
			size_t count, struct queue_limits *lim);
};

static ssize_t
queue_var_show(unsigned long var, char *page)
{
	return sysfs_emit(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 gendisk *disk, char *page)
{
	ssize_t ret;

	mutex_lock(&disk->queue->elevator_lock);
	ret = queue_var_show(disk->queue->nr_requests, page);
	mutex_unlock(&disk->queue->elevator_lock);
	return ret;
}

static ssize_t
queue_requests_store(struct gendisk *disk, const char *page, size_t count)
{
	unsigned long nr;
	int ret, err;
	unsigned int memflags;
	struct request_queue *q = disk->queue;

	if (!queue_is_mq(q))
		return -EINVAL;

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

	memflags = blk_mq_freeze_queue(q);
	mutex_lock(&q->elevator_lock);
	if (nr < BLKDEV_MIN_RQ)
		nr = BLKDEV_MIN_RQ;

	err = blk_mq_update_nr_requests(disk->queue, nr);
	if (err)
		ret = err;
	mutex_unlock(&q->elevator_lock);
	blk_mq_unfreeze_queue(q, memflags);
	return ret;
}

static ssize_t queue_ra_show(struct gendisk *disk, char *page)
{
	ssize_t ret;

	mutex_lock(&disk->queue->limits_lock);
	ret = queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page);
	mutex_unlock(&disk->queue->limits_lock);

	return ret;
}

static ssize_t
queue_ra_store(struct gendisk *disk, const char *page, size_t count)
{
	unsigned long ra_kb;
	ssize_t ret;
	unsigned int memflags;
	struct request_queue *q = disk->queue;

	ret = queue_var_store(&ra_kb, page, count);
	if (ret < 0)
		return ret;
	/*
	 * ->ra_pages is protected by ->limits_lock because it is usually
	 * calculated from the queue limits by queue_limits_commit_update.
	 */
	mutex_lock(&q->limits_lock);
	memflags = blk_mq_freeze_queue(q);
	disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
	mutex_unlock(&q->limits_lock);
	blk_mq_unfreeze_queue(q, memflags);

	return ret;
}

#define QUEUE_SYSFS_LIMIT_SHOW(_field)					\
static ssize_t queue_##_field##_show(struct gendisk *disk, char *page)	\
{									\
	return queue_var_show(disk->queue->limits._field, page);	\
}

QUEUE_SYSFS_LIMIT_SHOW(max_segments)
QUEUE_SYSFS_LIMIT_SHOW(max_discard_segments)
QUEUE_SYSFS_LIMIT_SHOW(max_integrity_segments)
QUEUE_SYSFS_LIMIT_SHOW(max_segment_size)
QUEUE_SYSFS_LIMIT_SHOW(max_write_streams)
QUEUE_SYSFS_LIMIT_SHOW(write_stream_granularity)
QUEUE_SYSFS_LIMIT_SHOW(logical_block_size)
QUEUE_SYSFS_LIMIT_SHOW(physical_block_size)
QUEUE_SYSFS_LIMIT_SHOW(chunk_sectors)
QUEUE_SYSFS_LIMIT_SHOW(io_min)
QUEUE_SYSFS_LIMIT_SHOW(io_opt)
QUEUE_SYSFS_LIMIT_SHOW(discard_granularity)
QUEUE_SYSFS_LIMIT_SHOW(zone_write_granularity)
QUEUE_SYSFS_LIMIT_SHOW(virt_boundary_mask)
QUEUE_SYSFS_LIMIT_SHOW(dma_alignment)
QUEUE_SYSFS_LIMIT_SHOW(max_open_zones)
QUEUE_SYSFS_LIMIT_SHOW(max_active_zones)
QUEUE_SYSFS_LIMIT_SHOW(atomic_write_unit_min