On 8/6/21 9:42 AM, Damien Le Moal wrote:

The ata device flag ATA_DFLAG_NCQ_PRIO indicates if a device supports
the NCQ Priority feature while the ATA_DFLAG_NCQ_PRIO_ENABLE device
flag indicates if the feature is enabled. Enabling NCQ priority use is
controlled by the user through the device sysfs attribute
ncq_prio_enable. As a result, the ATA_DFLAG_NCQ_PRIO flag should not be
cleared when ATA_DFLAG_NCQ_PRIO_ENABLE is not set as the device still
supports the feature even after the user disables it. This leads to the
following cleanups:
- In ata_build_rw_tf(), set a command high priority bit based on the
  ATA_DFLAG_NCQ_PRIO_ENABLE flag, not on the ATA_DFLAG_NCQ flag. That
  is, set a command high priority only if the user enabled NCQ priority
  use.
- In ata_dev_config_ncq_prio(), ATA_DFLAG_NCQ_PRIO should not be cleared
  if ATA_DFLAG_NCQ_PRIO_ENABLE is not set. If the device does not
  support NCQ priority, both ATA_DFLAG_NCQ_PRIO and
  ATA_DFLAG_NCQ_PRIO_ENABLE must be cleared.

With the above ata_dev_config_ncq_prio() change, ATA_DFLAG_NCQ_PRIO flag
is set on device scan and revalidation. There is no need to trigger a
device revalidation in ata_ncq_prio_enable_store() when the user enables
the use of NCQ priority. Remove the revalidation code from that funciton
to simplify it. Also change the return value from -EIO to -EINVAL when a
user tries to enable NCQ priority for a device that does not support
this feature.  While at it, also simplify ata_ncq_prio_enable_show().

Overall, there is no functional change introduced by this patch.

Signed-off-by: Damien Le Moal <redacted>
---
 drivers/ata/libata-core.c | 32 ++++++++++++++------------------
 drivers/ata/libata-sata.c | 37 ++++++++++++-------------------------
 2 files changed, 26 insertions(+), 43 deletions(-)

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
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