Commit 645a829e authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabled 



sysfs entry /sys/block/[device]/queue/wbt_lat_usec will be created even
if CONFIG_BLK_WBT is disabled, while read and write will always fail.
It doesn't make sense to create a sysfs entry that can't be accessed,
so don't create such entry.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230527010644.647900-2-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c6b7a3a2

block/blk-sysfs.c

+74 −69
Original line number Diff line number Diff line
@@ -47,19 +47,6 @@ queue_var_store(unsigned long *var, const char *page, size_t count) 
	return count;

}



static ssize_t queue_var_store64(s64 *var, const char *page)

{

	int err;

	s64 v;



	err = kstrtos64(page, 10, &v);

	if (err < 0)

		return err;



	*var = v;

	return 0;

}



static ssize_t queue_requests_show(struct request_queue *q, char *page)

{

	return queue_var_show(q->nr_requests, page);
@@ -451,61 +438,6 @@ static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page, 
	return count;

}



static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)

{

	if (!wbt_rq_qos(q))

		return -EINVAL;



	if (wbt_disabled(q))

		return sprintf(page, "0\n");



	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));

}



static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,

				  size_t count)

{

	struct rq_qos *rqos;

	ssize_t ret;

	s64 val;



	ret = queue_var_store64(&val, page);

	if (ret < 0)

		return ret;

	if (val < -1)

		return -EINVAL;



	rqos = wbt_rq_qos(q);

	if (!rqos) {

		ret = wbt_init(q->disk);

		if (ret)

			return ret;

	}



	if (val == -1)

		val = wbt_default_latency_nsec(q);

	else if (val >= 0)

		val *= 1000ULL;



	if (wbt_get_min_lat(q) == val)

		return count;



	/*

	 * Ensure that the queue is idled, in case the latency update

	 * ends up either enabling or disabling wbt completely. We can't

	 * have IO inflight if that happens.

	 */

	blk_mq_freeze_queue(q);

	blk_mq_quiesce_queue(q);



	wbt_set_min_lat(q, val);



	blk_mq_unquiesce_queue(q);

	blk_mq_unfreeze_queue(q);



	return count;

}



static ssize_t queue_wc_show(struct request_queue *q, char *page)

{

	if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
@@ -598,7 +530,6 @@ QUEUE_RW_ENTRY(queue_wc, "write_cache"); 
QUEUE_RO_ENTRY(queue_fua, "fua");

QUEUE_RO_ENTRY(queue_dax, "dax");

QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");

QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");

QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");

QUEUE_RO_ENTRY(queue_dma_alignment, "dma_alignment");
@@ -617,6 +548,78 @@ QUEUE_RW_ENTRY(queue_iostats, "iostats"); 
QUEUE_RW_ENTRY(queue_random, "add_random");

QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");



#ifdef CONFIG_BLK_WBT

static ssize_t queue_var_store64(s64 *var, const char *page)

{

	int err;

	s64 v;



	err = kstrtos64(page, 10, &v);

	if (err < 0)

		return err;



	*var = v;

	return 0;

}



static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)

{

	if (!wbt_rq_qos(q))

		return -EINVAL;



	if (wbt_disabled(q))

		return sprintf(page, "0\n");



	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));

}



static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,

				  size_t count)

{

	struct rq_qos *rqos;

	ssize_t ret;

	s64 val;



	ret = queue_var_store64(&val, page);

	if (ret < 0)

		return ret;

	if (val < -1)

		return -EINVAL;



	rqos = wbt_rq_qos(q);

	if (!rqos) {

		ret = wbt_init(q->disk);

		if (ret)

			return ret;

	}



	if (val == -1)

		val = wbt_default_latency_nsec(q);

	else if (val >= 0)

		val *= 1000ULL;



	if (wbt_get_min_lat(q) == val)

		return count;



	/*

	 * Ensure that the queue is idled, in case the latency update

	 * ends up either enabling or disabling wbt completely. We can't

	 * have IO inflight if that happens.

	 */

	blk_mq_freeze_queue(q);

	blk_mq_quiesce_queue(q);



	wbt_set_min_lat(q, val);



	blk_mq_unquiesce_queue(q);

	blk_mq_unfreeze_queue(q);



	return count;

}



QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");

#endif



static struct attribute *queue_attrs[] = {

	&queue_requests_entry.attr,

	&queue_ra_entry.attr,
@@ -655,7 +658,9 @@ static struct attribute *queue_attrs[] = { 
	&queue_wc_entry.attr,

	&queue_fua_entry.attr,

	&queue_dax_entry.attr,

#ifdef CONFIG_BLK_WBT

	&queue_wb_lat_entry.attr,

#endif

	&queue_poll_delay_entry.attr,

	&queue_io_timeout_entry.attr,

#ifdef CONFIG_BLK_DEV_THROTTLING_LOW

block/blk-wbt.h

+0 −19
Original line number Diff line number Diff line
@@ -18,10 +18,6 @@ u64 wbt_default_latency_nsec(struct request_queue *); 


#else



static inline int wbt_init(struct gendisk *disk)

{

	return -EINVAL;

}

static inline void wbt_disable_default(struct gendisk *disk)

{

}
@@ -31,21 +27,6 @@ static inline void wbt_enable_default(struct gendisk *disk) 
static inline void wbt_set_write_cache(struct request_queue *q, bool wc)

{

}

static inline u64 wbt_get_min_lat(struct request_queue *q)

{

	return 0;

}

static inline void wbt_set_min_lat(struct request_queue *q, u64 val)

{

}

static inline u64 wbt_default_latency_nsec(struct request_queue *q)

{

	return 0;

}

static inline bool wbt_disabled(struct request_queue *q)

{

	return true;

}



#endif /* CONFIG_BLK_WBT */