Commit 6451e203 authored by Yu Kuai's avatar Yu Kuai Committed by openeuler-sync-bot
Browse files

blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled 

mainline inclusion
from mainline-v6.2-rc1
commit 3642ef4d
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6Z1UG
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.3-rc7&id=3642ef4d95699193c4a461862382e643ae3720f0



----------------------------------------

Currently, if wbt is initialized and then disabled by
wbt_disable_default(), sysfs will still show valid wbt_lat_usec, which
will confuse users that wbt is still enabled.

This patch shows wbt_lat_usec as zero if it's disabled.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reported-and-tested-by: default avatarHolger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-5-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
(cherry picked from commit 18e44529)
parent 7478fbbb

block/blk-sysfs.c

+3 −0
Original line number Diff line number Diff line
@@ -461,6 +461,9 @@ 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));

}

block/blk-wbt.c

+8 −0
Original line number Diff line number Diff line
@@ -419,6 +419,14 @@ static void wbt_update_limits(struct rq_wb *rwb) 
	rwb_wake_all(rwb);

}



bool wbt_disabled(struct request_queue *q)

{

	struct rq_qos *rqos = wbt_rq_qos(q);



	return !rqos || RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT ||

	       RQWB(rqos)->enable_state == WBT_STATE_OFF_MANUAL;

}



u64 wbt_get_min_lat(struct request_queue *q)

{

	struct rq_qos *rqos = wbt_rq_qos(q);

block/blk-wbt.h

+5 −0
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ void wbt_enable_default(struct request_queue *); 


u64 wbt_get_min_lat(struct request_queue *q);

void wbt_set_min_lat(struct request_queue *q, u64 val);

bool wbt_disabled(struct request_queue *);



void wbt_set_write_cache(struct request_queue *, bool);
@@ -130,6 +131,10 @@ 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 */