[PATCH v3 0/5] Avoid that scsi-mq queue processing stalls

Bart Van Assche
2017-04-06T18:10:45Z

Hello Jens,

The five patches in this patch series fix the queue lockup I reported
recently on the linux-block mailing list. Please consider these patches
for inclusion in the upstream kernel.

Thanks,

Bart.

Changes between v2 and v3:
- Removed the blk_mq_ops.restart_hctx function pointer again.
- Modified blk_mq_sched_restart_queues() such that only a single hardware
queue is restarted instead of multiple if hardware queues are shared.
- Introduced a new function in the block layer, namely
blk_mq_delay_run_hw_queue().

Changes between v1 and v2:
- Reworked scsi_restart_queues() such that it no longer takes the SCSI
host lock.
- Added two patches - one for exporting blk_mq_sched_restart_hctx() and
another one to make iterating with RCU over blk_mq_tag_set.tag_list safe.

Bart Van Assche (5):
blk-mq: Make it safe to use RCU to iterate over
blk_mq_tag_set.tag_list
blk-mq: Restart a single queue if tag sets are shared
blk-mq: Clarify comments in blk_mq_dispatch_rq_list()
blk-mq: Introduce blk_mq_delay_run_hw_queue()
scsi: Avoid that SCSI queues get stuck

block/blk-mq-sched.c | 60 +++++++++++++++++++++++++++++++++++--------
block/blk-mq-sched.h | 16 +-----------
block/blk-mq.c | 68 +++++++++++++++++++++++++++++++++++++++----------
drivers/scsi/scsi_lib.c | 6 ++---
include/linux/blk-mq.h | 2 ++
include/linux/blkdev.h | 1 -
6 files changed, 111 insertions(+), 42 deletions(-)

--
2.12.0