Commit 58768b05 authored by Igor Pylypiv's avatar Igor Pylypiv Committed by Damien Le Moal
Browse files

ata: libata-scsi: Fix CDL control 



Delete extra checks for the ATA_DFLAG_CDL_ENABLED flag that prevent
SET FEATURES command from being issued to a drive when NCQ commands
are active.

ata_mselect_control_ata_feature() sets / clears the ATA_DFLAG_CDL_ENABLED
flag during the translation of MODE SELECT to SET FEATURES. If SET FEATURES
gets deferred due to outstanding NCQ commands, the original MODE SELECT
command will be re-queued. When the re-queued MODE SELECT goes through
the ata_mselect_control_ata_feature() translation again, SET FEATURES
will not be issued because ATA_DFLAG_CDL_ENABLED has been already set or
cleared by the initial translation of MODE SELECT.

The ATA_DFLAG_CDL_ENABLED checks in ata_mselect_control_ata_feature()
are safe to remove because scsi_cdl_enable() implements a similar logic
that avoids enabling CDL if it has been enabled already.

Fixes: 17e897a4 ("ata: libata-scsi: Improve CDL control")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarIgor Pylypiv <ipylypiv@google.com>
Reviewed-by: default avatarNiklas Cassel <cassel@kernel.org>
Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
parent 35f6bedc

drivers/ata/libata-scsi.c

+3 −8
Original line number Diff line number Diff line
@@ -3904,21 +3904,16 @@ static int ata_mselect_control_ata_feature(struct ata_queued_cmd *qc, 
	/* Check cdl_ctrl */

	switch (buf[0] & 0x03) {

	case 0:

		/* Disable CDL if it is enabled */

		if (!(dev->flags & ATA_DFLAG_CDL_ENABLED))

			return 0;

		/* Disable CDL */

		ata_dev_dbg(dev, "Disabling CDL\n");

		cdl_action = 0;

		dev->flags &= ~ATA_DFLAG_CDL_ENABLED;

		break;

	case 0x02:

		/*

		 * Enable CDL if not already enabled. Since this is mutually

		 * exclusive with NCQ priority, allow this only if NCQ priority

		 * is disabled.

		 * Enable CDL. Since CDL is mutually exclusive with NCQ

		 * priority, allow this only if NCQ priority is disabled.

		 */

		if (dev->flags & ATA_DFLAG_CDL_ENABLED)

			return 0;

		if (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED) {

			ata_dev_err(dev,

				"NCQ priority must be disabled to enable CDL\n");