path: root/block/blk-mq-debugfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Facebook
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/build_bug.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"

static int queue_poll_stat_show(void *data, struct seq_file *m)
{
	return 0;
}

#define TO_REQUEST_QUEUE(m) ((struct request_queue *)m->private)

static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
	__acquires(&TO_REQUEST_QUEUE(m)->requeue_lock)
{
	struct request_queue *q = m->private;

	spin_lock_irq(&q->requeue_lock);
	return seq_list_start(&q->requeue_list, *pos);
}

static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct request_queue *q = m->private;

	return seq_list_next(v, &q->requeue_list, pos);
}

static void queue_requeue_list_stop(struct seq_file *m, void *v)
	__releases(&TO_REQUEST_QUEUE(m)->requeue_lock)
{
	struct request_queue *q = m->private;

	spin_unlock_irq(&q->requeue_lock);
}

#undef TO_REQUEST_QUEUE

static const struct seq_operations queue_requeue_list_seq_ops = {
	.start	= queue_requeue_list_start,
	.next	= queue_requeue_list_next,
	.stop	= queue_requeue_list_stop,
	.show	= blk_mq_debugfs_rq_show,
};

static int blk_flags_show(struct seq_file *m, const unsigned long flags,
			  const char *const *flag_name, int flag_name_count)
{
	bool sep = false;
	int i;

	for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
		if (!(flags & BIT(i)))
			continue;
		if (sep)
			seq_puts(m, "|");
		sep = true;
		if (i < flag_name_count && flag_name[i])
			seq_puts(m, flag_name[i]);
		else
			seq_printf(m, "%d", i);
	}
	return 0;
}

static int queue_pm_only_show(void *data, struct seq_file *m)
{
	struct request_queue *q = data;

	seq_printf(m, "%d\n", atomic_read(&q->pm_only));
	return 0;
}

#define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
static const char *const blk_queue_flag_name[] = {
	QUEUE_FLAG_NAME(DYING),
	QUEUE_FLAG_NAME(NOMERGES),
	QUEUE_FLAG_NAME(SAME_COMP),
	QUEUE_FLAG_NAME(FAIL_IO),
	QUEUE_FLAG_NAME(NOXMERGES),
	QUEUE_FLAG_NAME(SAME_FORCE),
	QUEUE_FLAG_NAME(INIT_DONE),
	QUEUE_FLAG_NAME(STATS),
	QUEUE_FLAG_NAME(REGISTERED),
	QUEUE_FLAG_NAME(QUIESCED),
	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
	QUEUE_FLAG_NAME(HCTX_ACTIVE),
	QUEUE_FLAG_NAME(SQ_SCHED),
	QUEUE_FLAG_NAME(DISABLE_WBT_DEF),
	QUEUE_FLAG_NAME(NO_ELV_SWITCH),
	QUEUE_FLAG_NAME(QOS_ENABLED),
	QUEUE_FLAG_NAME(BIO_ISSUE_TIME),
	QUEUE_FLAG_NAME(ZONED_QD1_WRITES),
};
#undef QUEUE_FLAG_NAME

static int queue_state_show(void *data, struct seq_file *m)
{
	struct request_queue *q = data;

	BUILD_BUG_ON(ARRAY_SIZE(blk_queue_flag_name) != QUEUE_FLAG_MAX);
	blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
		       ARRAY_SIZE(blk_queue_flag_name));
	seq_puts(m, "\n");
	return 0;
}

static ssize_t queue_state_write(void *data, const char __user *buf,
				 size_t count, loff_t *ppos)
{
	struct request_queue *q = data;
	char opbuf[16] = { }, *op;

	/*
	 * The "state" attribute is removed when the queue is removed.  Don't
	 * allow setting the state on a dying queue to avoid a use-after-free.
	 */
	if (blk_queue_dying(q))
		return -ENOENT;

	if (count >= sizeof(opbuf)) {
		pr_err("%s: operation too long\n", __func__);
		goto inval;
	}

	if (copy_from_user(opbuf, buf, count))
		return -EFAULT;
	op = strstrip(opbuf);
	if (strcmp(op, "run") == 0) {
		blk_mq_run_hw_queues(q, true);
	} else if (strcmp(op, "start") == 0) {
		blk_mq_start_stopped_hw_queues(q, true);
	} else if (strcmp(op, "kick") == 0) {
		blk_mq_kick_requeue_list(q);
	} else {
		pr_err("%s: unsupported operation '%s'\n", __func__, op);
inval:
		pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
		return -EINVAL;
	}
	return count;
}

static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
	{ "poll_stat", 0400, queue_poll_stat_show },
	{ "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
	{ "pm_only", 0600, queue_pm_only_show, NULL },
	{ "state", 0600, queue_state_show,