kernel/linux.git/block/blk-stat.c, branch v6.1.168

block: prevent division by zero in blk_rq_stat_sum()

2024-04-13T11:05:12+00:00

[ Upstream commit 93f52fbeaf4b676b21acfe42a5152620e6770d02 ] The expression dst->nr_samples + src->nr_samples may have zero value on overflow. It is necessary to add a check to avoid division by zero. Found by Linux Verification Center (linuxtesting.org) with Svace. Signed-off-by: Roman Smirnov Reviewed-by: Sergey Shtylyov Link: https://lore.kernel.org/r/20240305134509.23108-1-r.smirnov@omp.ru Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-stat: fix QUEUE_FLAG_STATS clear

2023-05-11T14:03:00+00:00

commit 20de765f6d9da0c47b756429c60b41063b990a10 upstream. We need to set QUEUE_FLAG_STATS for two cases: 1. blk_stat_enable_accounting() 2. blk_stat_add_callback() So we should clear it only when ((q->stats->accounting == 0) && list_empty(&q->stats->callbacks)). blk_stat_disable_accounting() only check if q->stats->accounting is 0 before clear the flag, this patch fix it. Also add list_empty(&q->stats->callbacks)) check when enable, or the flag is already set. The bug can be reproduced on kernel without BLK_DEV_THROTTLING (since it unconditionally enable accounting, see the next patch). # cat /sys/block/sr0/queue/scheduler none mq-deadline [bfq] # cat /sys/kernel/debug/block/sr0/state SAME_COMP|IO_STAT|INIT_DONE|STATS|REGISTERED|NOWAIT|30 # echo none > /sys/block/sr0/queue/scheduler # cat /sys/kernel/debug/block/sr0/state SAME_COMP|IO_STAT|INIT_DONE|REGISTERED|NOWAIT # cat /sys/block/sr0/queue/wbt_lat_usec 75000 We can see that after changing elevator from "bfq" to "none", "STATS" flag is lost even though WBT callback still need it. Fixes: 68497092bde9 ("block: make queue stat accounting a reference") Cc: # v5.17+ Signed-off-by: Chengming Zhou Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20230413062805.2081970-1-chengming.zhou@linux.dev Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: make queue stat accounting a reference

2021-12-15T00:23:05+00:00

kyber turns on IO statistics when it is loaded on a queue, which means that even if kyber is then later unloaded, we're still stuck with stats enabled on the queue. Change the account enabled from a bool to an int, and pair the enable call with the equivalent disable call. This ensures that stats gets turned off again appropriately. Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe

block: only allocate poll_stats if there's a user of them

2021-11-29T13:38:35+00:00

This is essentially never used, yet it's about 1/3rd of the total queue size. Allocate it when needed, and don't embed it in the queue. Kill the queue flag for this while at it, since we can just check the assigned pointer now. Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-stat: make q->stats->lock irqsafe

2020-09-01T22:48:46+00:00

blk-iocost calls blk_stat_enable_accounting() while holding an irqsafe lock which triggers a lockdep splat because q->stats->lock isn't irqsafe. Let's make it irqsafe. Signed-off-by: Tejun Heo Fixes: cd006509b0a9 ("blk-iocost: account for IO size when testing latencies") Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Jens Axboe

blk-stat: Optimise blk_stat_add()

2019-10-08T03:19:10+00:00

blk_stat_add() calls {get,put}_cpu_ptr() in a loop, which entails overhead of disabling/enabling preemption. The loop is under RCU (i.e.short) anyway, so do get_cpu() in advance. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe

block: add SPDX tags to block layer files missing licensing information

2019-04-30T22:12:03+00:00

Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to those. Reviewed-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove a few unused exports

2018-11-15T19:13:25+00:00

Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: export blk_stat_enable_accounting()

2018-09-27T23:34:54+00:00

Kyber will need this in a future change if it is built as a module. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

blk-stat: export helpers for modifying blk_rq_stat

2018-07-09T15:07:54+00:00

We need to use blk_rq_stat in the blkcg qos stuff, so export some of these helpers so they can be used by other things. Signed-off-by: Josef Bacik Acked-by: Tejun Heo Signed-off-by: Jens Axboe