[PATCH 2/8] ata: libata-scsi: do not accept subpage code FFh in MODE SELECT

[Niklas Cassel <cassel@kernel.org>]

When the SUBPAGE CODE of the mode page in a MODE SELECT parameter list
is FFh, ata_scsi_mode_select_xlat() rejects it for the control mode
page, but accepts it for all other mode pages, i.e. for the caching
mode page, the only other mode page that it supports.

However, FFh is not the subpage code of an actual mode page: SPC-7
(7.5.2) only defines it as the MODE SENSE request code for all
subpages. SUBPAGE CODE FFh only means "all subpages" in requests, i.e.
in the MODE SENSE CDB for mode pages and in the LOG SELECT CDB for log
pages (see SPC-5, 6.8), while the SUBPAGE CODE of a mode page in a MODE
SELECT parameter list identifies a specific mode page. Also, SAT-2 and
later versions of SAT define the Caching mode page with the SPF bit set
to zero (see SAT-6, 10.4.9), i.e. without a SUBPAGE CODE field.

Remove the ALL_SUB_MPAGES case, so that SUBPAGE CODE FFh is rejected
like any other unsupported subpage.

Fixes: 1b26d29ccd59 ("[libata] scsi: implement MODE SELECT command")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libata-scsi.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7081caa8eb93..d7923bc664d6 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4643,19 +4643,11 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 	}
 
 	/*
-	 * Supported subpages: all subpages and ATA feature sub-page f2h of
-	 * the control page.
+	 * The only supported subpage is the ATA feature sub-page f2h of the
+	 * control page.
 	 */
 	if (spg) {
 		switch (spg) {
-		case ALL_SUB_MPAGES:
-			/* All subpages is not supported for the control page */
-			if (pg == CONTROL_MPAGE) {
-				fp = (p[0] & 0x40) ? 1 : 0;
-				fp += hdr_len + bd_len;
-				goto invalid_param;
-			}
-			break;
 		case ATA_FEATURE_SUB_MPAGE:
 			if (qc->dev->flags & ATA_DFLAG_CDL &&
 			    pg == CONTROL_MPAGE)
-- 
2.56.0