[PATCH v4 0/5] ufs: Do not requeue while ungating the clock

Bart Van Assche
2023-05-29T20:26:51Z

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 v3:
- Added a patch that removes two duplicate declarations.

Changes compared to v2:
- Only enable BLK_MQ_F_BLOCKING if clock gating is supported.
- Introduce flag queuecommand_may_block in both the SCSI host and SCSI host
template data structures.

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

Bart Van Assche (5):
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: Declare ufshcd_{hold,release}() once
scsi: ufs: Ungate the clock synchronously

drivers/scsi/hosts.c | 1 +
drivers/scsi/scsi_lib.c | 27 ++++++----
drivers/ufs/core/ufs-sysfs.c | 2 +-
drivers/ufs/core/ufshcd-crypto.c | 2 +-
drivers/ufs/core/ufshcd-priv.h | 3 --
drivers/ufs/core/ufshcd.c | 87 ++++++++++----------------------
include/scsi/scsi_host.h | 6 +++
include/ufs/ufshcd.h | 2 +-
8 files changed, 54 insertions(+), 76 deletions(-)