libata: add qc_fill_rtf port operation

On command completion, ata_qc_complete() directly called ops->tf_read
to fill qc->result_tf.  This patch adds ops->qc_fill_rtf to replace
hardcoded ops->tf_read usage.

ata_sff_qc_fill_rtf() which uses ops->tf_read to fill result_tf is
implemented and set in ata_base_port_ops and other ops tables which
don't inherit from ata_base_port_ops, so this patch doesn't introduce
any behavior change.

ops->qc_fill_rtf() is similar to ops->sff_tf_read() but can only be
called when a command finishes.  As some non-SFF controllers don't
have TF registers defined unless they're associated with in-flight
commands, this limited operation makes life easier for those drivers
and help lifting SFF assumptions from libata core layer.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index a1664b87927a..2ec255839dcd 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -356,6 +356,7 @@ static struct ata_port_operations sas_sata_ops = {
         .sff_tf_read            = sas_ata_tf_read,
         .qc_prep                = ata_noop_qc_prep,
         .qc_issue               = sas_ata_qc_issue,
+        .qc_fill_rtf            = ata_sff_qc_fill_rtf,
         .port_start             = ata_sas_port_start,
         .port_stop              = ata_sas_port_stop,
         .scr_read               = sas_ata_scr_read,