Hi,
Qian reported there is hang during booting when shared host tagset is
introduced on megaraid sas. Sumit reported the whole SCSI probe takes
about ~45min in his test.
Turns out it is caused by nr_hw_queues increased, especially commit
b3c6a5997541("block: Fix a lockdep complaint triggered by request queue flushing")
adds synchronize_rcu() for each hctx's release handler.
Address the original lockdep false positive warning by simpler way, then
long scsi probe can be avoided with lockdep enabled.
V2:
- add reviewed-by
- adjust commit log of patch 3
Ming Lei (3):
blk-mq: add new API of blk_mq_hctx_set_fq_lock_class
nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class
Revert "block: Fix a lockdep complaint triggered by request queue
flushing"
block/blk-flush.c | 30 +++++++++++++++++++++++++-----
block/blk.h | 1 -
drivers/nvme/target/loop.c | 10 ++++++++++
include/linux/blk-mq.h | 3 +++
4 files changed, 38 insertions(+), 6 deletions(-)
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Qian Cai <cai@xxxxxxxxxx>
Cc: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx>
Cc: John Garry <john.garry@xxxxxxxxxx>
Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
--
2.28.0
