[PATCH V2 0/5] blk-mq: Wait for for hctx inflight requests on CPU unplug

Ming Lei
2019-05-27T15:02:46Z

Hi,

blk-mq drivers often use managed IRQ, which affinity is setup
automatically by genirq core.

For managed IRQ, we need to make sure that there isn't in-flight
requests when the managed IRQ is going to shutdown.

This patch waits for inflight requests associated with one
going-to-shutdown managed IRQ in blk-mq's CPU hotplug handler.

One special case is that some SCSI devices have multiple private
completion(reply) queue even though they only have one blk-mq hw queue,
and the private completion queue is associated with one managed
IRQ. Wait for inflight requests for these SCSI device too if last
CPU of the completion queue is going to shutdown.

SCSI device's internal commands aren't covered in this patchset,
and they are much less important than requests from blk-mq/scsi
core.

V2:
- cover private multiple completion(reply) queue
- remove timeout during waitting, because some driver doesn't
implemnt proper .timeout handler.

Ming Lei (5):
scsi: select reply queue from request's CPU
blk-mq: introduce .complete_queue_affinity
scsi: core: implement callback of .complete_queue_affinity
scsi: implement .complete_queue_affinity
blk-mq: Wait for for hctx inflight requests on CPU unplug

block/blk-mq-tag.c | 2 +-
block/blk-mq-tag.h | 5 ++
block/blk-mq.c | 94 +++++++++++++++++++--
drivers/scsi/hisi_sas/hisi_sas_main.c | 5 +-
drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 11 +++
drivers/scsi/hpsa.c | 14 ++-
drivers/scsi/megaraid/megaraid_sas_base.c | 10 +++
drivers/scsi/megaraid/megaraid_sas_fusion.c | 4 +-
drivers/scsi/mpt3sas/mpt3sas_base.c | 16 ++--
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 11 +++
drivers/scsi/scsi_lib.c | 14 +++
include/linux/blk-mq.h | 12 ++-
include/scsi/scsi_cmnd.h | 11 +++
include/scsi/scsi_host.h | 10 +++
14 files changed, 197 insertions(+), 22 deletions(-)

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2.20.1