6.14-stable review patch. If anyone has any objections, please let me know.
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From: Damien Le Moal dlemoal@kernel.org
commit 17e897a456752ec9c2d7afb3d9baf268b442451b upstream.
With ATA devices supporting the CDL feature, using CDL requires that the feature be enabled with a SET FEATURES command. This command is issued as the translated command for the MODE SELECT command issued by scsi_cdl_enable() when the user enables CDL through the device cdl_enable sysfs attribute.
Currently, ata_mselect_control_ata_feature() always translates a MODE SELECT command for the ATA features subpage of the control mode page to a SET FEATURES command to enable or disable CDL based on the cdl_ctrl field. However, there is no need to issue the SET FEATURES command if: 1) The MODE SELECT command requests disabling CDL and CDL is already disabled. 2) The MODE SELECT command requests enabling CDL and CDL is already enabled.
Fix ata_mselect_control_ata_feature() to issue the SET FEATURES command only when necessary. Since enabling CDL also implies a reset of the CDL statistics log page, avoiding useless CDL enable operations also avoids clearing the CDL statistics log.
Also add debug messages to clearly signal when CDL is being enabled or disabled using a SET FEATURES command.
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 Reviewed-by: Niklas Cassel cassel@kernel.org Reviewed-by: Igor Pylypiv ipylypiv@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/ata/libata-scsi.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -3909,17 +3909,27 @@ static unsigned int ata_mselect_control_ /* Check cdl_ctrl */ switch (buf[0] & 0x03) { case 0: - /* Disable CDL */ + /* Disable CDL if it is enabled */ + if (!(dev->flags & ATA_DFLAG_CDL_ENABLED)) + return 0; + ata_dev_dbg(dev, "Disabling CDL\n"); cdl_action = 0; dev->flags &= ~ATA_DFLAG_CDL_ENABLED; break; case 0x02: - /* Enable CDL T2A/T2B: NCQ priority must be disabled */ + /* + * Enable CDL if not already enabled. Since this 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"); return -EINVAL; } + ata_dev_dbg(dev, "Enabling CDL\n"); cdl_action = 1; dev->flags |= ATA_DFLAG_CDL_ENABLED; break;