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| author | Zhang Yi <yi.zhang@huawei.com> | 2021-06-19 11:36:59 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-06-21 23:03:41 +0200 |
| commit | 1d0903d61e9645c6330b94247b96dd873dfc11c8 (patch) | |
| tree | a46e127deb8156f8a2390770c36d0a070a126749 /block/blk-wbt.c | |
| parent | block/mq-deadline: Prioritize high-priority requests (diff) | |
| download | linux-1d0903d61e9645c6330b94247b96dd873dfc11c8.tar.xz linux-1d0903d61e9645c6330b94247b96dd873dfc11c8.zip | |
blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled()
Now that we disable wbt by simply zero out rwb->wb_normal in
wbt_disable_default() when switch elevator to bfq, but it's not safe
because it will become false positive if we change queue depth. If it
become false positive between wbt_wait() and wbt_track() when submit
write request, it will lead to drop rqw->inflight to -1 in wbt_done(),
which will end up trigger IO hung. Fix this issue by introduce a new
state which mean the wbt was disabled.
Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210619093700.920393-2-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-wbt.c')
| -rw-r--r-- | block/blk-wbt.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-wbt.c b/block/blk-wbt.c index b363b0532704..0ce0883df3d6 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -77,7 +77,8 @@ enum { static inline bool rwb_enabled(struct rq_wb *rwb) { - return rwb && rwb->wb_normal != 0; + return rwb && rwb->enable_state != WBT_STATE_OFF_DEFAULT && + rwb->wb_normal != 0; } static void wb_timestamp(struct rq_wb *rwb, unsigned long *var) @@ -701,7 +702,7 @@ void wbt_disable_default(struct request_queue *q) rwb = RQWB(rqos); if (rwb->enable_state == WBT_STATE_ON_DEFAULT) { blk_stat_deactivate(rwb->cb); - rwb->wb_normal = 0; + rwb->enable_state = WBT_STATE_OFF_DEFAULT; } } EXPORT_SYMBOL_GPL(wbt_disable_default); |