[PATCH v2 2/5] ata: libata-scsi: Fail MODE SELECT for unsupported mode pages

[Damien Le Moal <dlemoal@kernel.org>]

For devices that do not support CDL, the subpage F2h of the control mode
page 0Ah should not be supported. However, the function
ata_mselect_control_ata_feature() does not fail for a device that does
not have the ATA_DFLAG_CDL device flag set, which can lead to an invalid
SET FEATURES command (which will be failed by the device) to be issued.

Modify ata_mselect_control_ata_feature() to return -EOPNOTSUPP if it is
executed for a device without CDL support. This error code is checked by
ata_scsi_mode_select_xlat() (through ata_mselect_control()) to fail the
MODE SELECT command immediately with an ILLEGAL REQUEST / INVALID FIELD
IN CDB asc/ascq as mandated by the SPC specifications for unsupported
mode pages.

Fixes: df60f9c64576 ("scsi: ata: libata: Add ATA feature control sub-page translation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/ata/libata-scsi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 24e662c837e3..15661b05cb48 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3896,6 +3896,15 @@ static int ata_mselect_control_ata_feature(struct ata_queued_cmd *qc,
 	struct ata_taskfile *tf = &qc->tf;
 	u8 cdl_action;
 
+	/*
+	 * The sub-page f2h should only be supported for devices that support
+	 * the T2A and T2B command duration limits mode pages (note here the
+	 * "should" which is what SAT-6 defines). So fail this command if the
+	 * device does not support CDL.
+	 */
+	if (!(dev->flags & ATA_DFLAG_CDL))
+		return -EOPNOTSUPP;
+
 	/*
 	 * The first four bytes of ATA Feature Control mode page are a header,
 	 * so offsets in mpage are off by 4 compared to buf.  Same for len.
@@ -4101,6 +4110,8 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 	case CONTROL_MPAGE:
 		ret = ata_mselect_control(qc, spg, p, pg_len, &fp);
 		if (ret < 0) {
+			if (ret == -EOPNOTSUPP)
+				goto invalid_fld;
 			fp += hdr_len + bd_len;
 			goto invalid_param;
 		}
-- 
2.49.0