[v2,0/3] scsi: add attribute to set lun queue depth on all luns on shost

Message

James Smart Jan. 23, 2020, 10:20 p.m. UTC

There has been a desire to set the lun queue depth on all luns on an
shost. Today that is done by an external script looping through
discovered sdevs and set an sdev attribute. The desire is to have a
single shost attribute that performs this work removing the requirement
for scripting.

This patch:
- Refactors the existing sdev change max queue depth attribute so the
  meat of it becomes a service routine.
- Creates a shost helper routine, lldd callable, which cycles though
  all sdevs on the shost and changes their max queue depth. Uses the
  new service routine.
- Adds a new shost attribute which calls the new shost helper routine.

v2:
Reworked the patch with recommendations on error returns and breaking into
smaller patches. I also had a request to make the shost change routine to
be lldd callable. So switched up how that was implemented as well.

-- james

James Smart (3):
  scsi: refactor sdev lun queue depth setting via sysfs
  scsi: add shost helper to set max queue depth on all of its devices
  scsi: add shost attribute to set max queue depth on all devices on the
    shost

 drivers/scsi/scsi.c        | 54 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/scsi_priv.h   |  1 +
 drivers/scsi/scsi_sysfs.c  | 27 +++++++++++++++++------
 include/scsi/scsi_device.h |  1 +
 4 files changed, 77 insertions(+), 6 deletions(-)