[v3,0/4] ufs: Do not requeue while ungating the clock

Message

Bart Van Assche May 26, 2023, 5:29 p.m. UTC

Hi Martin,

In the traces we recorded while testing zoned storage we noticed that UFS
commands are requeued while the clock is being ungated. Command requeueing
makes it harder than necessary to preserve the command order. Hence this
patch series that modifies the SCSI core and also the UFS driver such that
clock ungating does not trigger command requeueing.

Please consider this patch series for the next merge window.

Thanks,

Bart.

Changes compared to v2:
- Only enable BLK_MQ_F_BLOCKING if necessary.

Changes compared to v1:
- Dropped patch "scsi: ufs: core: Unexport ufshcd_hold() and ufshcd_release()".
- Removed a ufshcd_scsi_block_requests() / ufshcd_scsi_unblock_requests() pair
  from patch "scsi: ufs: Ungate the clock synchronously".

Bart Van Assche (4):
  scsi: core: Rework scsi_host_block()
  scsi: core: Support setting BLK_MQ_F_BLOCKING
  scsi: ufs: Conditionally enable the BLK_MQ_F_BLOCKING flag
  scsi: ufs: Ungate the clock synchronously

 drivers/scsi/hosts.c             |  1 +
 drivers/scsi/scsi_lib.c          | 26 +++++-----
 drivers/ufs/core/ufs-sysfs.c     |  2 +-
 drivers/ufs/core/ufshcd-crypto.c |  2 +-
 drivers/ufs/core/ufshcd-priv.h   |  2 +-
 drivers/ufs/core/ufshcd.c        | 85 ++++++++++----------------------
 include/scsi/scsi_host.h         |  6 +++
 include/ufs/ufshcd.h             |  2 +-
 8 files changed, 53 insertions(+), 73 deletions(-)