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

/*
 * Copyright (C) 2017 Facebook
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/debugfs.h>

#include <linux/blk-mq.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-tag.h"

static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
{
	if (stat->nr_samples) {
		seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
			   stat->nr_samples, stat->mean, stat->min, stat->max);
	} else {
		seq_puts(m, "samples=0");
	}
}

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

	for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
		seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
		print_stat(m, &q->poll_stat[2*bucket]);
		seq_puts(m, "\n");

		seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
		print_stat(m, &q->poll_stat[2*bucket+1]);
		seq_puts(m, "\n");
	}
	return 0;
}

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

	spin_unlock_irq(&q->requeue_lock);
}

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(QUEUED),
	QUEUE_FLAG_NAME(STOPPED),
	QUEUE_FLAG_NAME(DYING),
	QUEUE_FLAG_NAME(BYPASS),
	QUEUE_FLAG_NAME(BIDI),
	QUEUE_FLAG_NAME(NOMERGES),
	QUEUE_FLAG_NAME(SAME_COMP),
	QUEUE_FLAG_NAME(FAIL_IO),
	QUEUE_FLAG_NAME(NONROT),
	QUEUE_FLAG_NAME(IO_STAT),
	QUEUE_FLAG_NAME(DISCARD),
	QUEUE_FLAG_NAME(NOXMERGES),
	QUEUE_FLAG_NAME(ADD_RANDOM),
	QUEUE_FLAG_NAME(SECERASE),
	QUEUE_FLAG_NAME(SAME_FORCE),
	QUEUE_FLAG_NAME(DEAD),
	QUEUE_FLAG_NAME(INIT_DONE),
	QUEUE_FLAG_NAME(NO_SG_MERGE),
	QUEUE_FLAG_NAME(POLL),
	QUEUE_FLAG_NAME(WC),
	QUEUE_FLAG_NAME(FUA),
	QUEUE_FLAG_NAME(FLUSH_NQ),
	QUEUE_FLAG_NAME(DAX),
	QUEUE_FLAG_NAME(STATS),
	QUEUE_FLAG_NAME(POLL_STATS),
	QUEUE_FLAG_NAME(REGISTERED),
	QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),
	QUEUE_FLAG_NAME(QUIESCED),
};
#undef QUEUE_FLAG_NAME

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

	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 after blk_cleanup_queue() has called
	 * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
	 * triggering a use-after-free.
	 */
	if (blk_queue_dead(q))
		return -ENOENT;

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

	if (copy_from_user(opbuf, <