kernel/linux.git/block/blk-stat.c, branch v6.6.131

block: prevent division by zero in blk_rq_stat_sum()

2024-04-13T11:07:37+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-mq: include in block/blk-mq.h

2023-04-13T12:52:29+00:00

block/blk-mq.h needs various definitions from , include it there instead of relying on the source files to include both. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20230413064057.707578-4-hch@lst.de Signed-off-by: Jens Axboe

blk-stat: fix QUEUE_FLAG_STATS clear

2023-04-13T12:48:11+00:00

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

blk-mq: remove hybrid polling

2023-03-20T21:30:03+00:00

io_uring provides the only way user space can poll completions, and that always sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling dead code, so remove it and everything supporting it. Hybrid polling was effectively killed off with 9650b453a3d4b1, "block: ignore RWF_HIPRI hint for sync dio", but still potentially reachable through io_uring until d729cf9acb93119, "io_uring: don't sleep when polling for I/O", but hybrid polling probably should not have been reachable through that async interface from the beginning. Fixes: 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio") Fixes: d729cf9acb93 ("io_uring: don't sleep when polling for I/O") Signed-off-by: Keith Busch Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.com Signed-off-by: Jens Axboe

block: don't call blk_throtl_stat_add for non-READ/WRITE commands

2023-02-03T15:20:04+00:00

blk_throtl_stat_add is called from blk_stat_add explicitly, unlike the other stats that go through q->stats->callbacks. To prepare for cgroup data moving to the gendisk, ensure blk_throtl_stat_add is only called for the plain READ and WRITE commands that it actually handles internally, as blk_stat_add can also be called for passthrough commands on queues that do not have a gendisk associated with them. Signed-off-by: Christoph Hellwig Reviewed-by: Andreas Herrmann Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20230203150400.3199230-2-hch@lst.de Signed-off-by: Jens Axboe

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