[PATCH 7/8] ata: libata-scsi: set the field pointer when rejecting CDL

[Niklas Cassel <cassel@kernel.org>]

From: Shao Mingyin <shao.mingyin@zte.com.cn>

ata_mselect_control_ata_feature() rejects enabling CDL while NCQ
priority is enabled, but unlike its other error branches it returns
without setting *fp.

ata_scsi_mode_select_xlat() initializes fp to 0xffff and, when the
handler fails, adds the offset of the mode page in the parameter list
to it, i.e. the length of the mode parameter header and of the block
descriptors. As fp is a u16, this wraps around, so the resulting sense
data reports the byte before the mode page, i.e. the last byte of the
mode parameter header or of the block descriptors, as the FIELD
POINTER, instead of the byte containing the CDL_CTRL field that
requests enabling CDL.

Set *fp to 4, i.e. to the byte containing the CDL_CTRL field, like the
branch rejecting an invalid CDL_CTRL value does.

Fixes: df60f9c64576 ("scsi: ata: libata: Add ATA feature control sub-page translation")
Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
[cassel: set *fp to 4, the offset of CDL_CTRL in the mode page]
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libata-scsi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 3257bbbba5b6..e91920659c22 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4521,6 +4521,7 @@ static int ata_mselect_control_ata_feature(struct ata_queued_cmd *qc,
 		if (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED) {
 			ata_dev_err(dev,
 				"NCQ priority must be disabled to enable CDL\n");
+			*fp = 4;
 			return -EINVAL;
 		}
 		ata_dev_dbg(dev, "Enabling CDL\n");
-- 
2.56.0