[PATCH v7 7/7] ata: libata: Enable fua support by default

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

Change the default value of the fua module parameter to 1 to enable fua
support by default for all devices supporting it.

With this change, ata_dev_config_fua() will now set the flag
ATA_DFLAG_FUA by default for devices that support FUA. This will cause
ata_scsiop_mode_sense() to set the DPOFUA bit in the DEVICE-SPECIFIC
PARAMETER field in the mode parameter header. The SCSI disk driver
performs a MODE SENSE and looks at the DPOFUA bit, it then calls
blk_queue_write_cache() with the value of the DPOFUA bit, to inform the
block layer if FUA is supported or not. The block layer will not issue
REQ_FUA requests if it has not been informed that the device actually
support FUA.

FUA support can be disabled for all drives or for individual drives
using the force=[ID]nofua libata module argument.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 97ade977b830..2967671131d2 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -127,9 +127,9 @@ int atapi_passthru16 = 1;
 module_param(atapi_passthru16, int, 0444);
 MODULE_PARM_DESC(atapi_passthru16, "Enable ATA_16 passthru for ATAPI devices (0=off, 1=on [default])");
 
-int libata_fua = 0;
+int libata_fua = 1;
 module_param_named(fua, libata_fua, int, 0444);
-MODULE_PARM_DESC(fua, "FUA support (0=off [default], 1=on)");
+MODULE_PARM_DESC(fua, "FUA support (0=off, 1=on [default])");
 
 static int ata_ignore_hpa;
 module_param_named(ignore_hpa, ata_ignore_hpa, int, 0644);
-- 
2.39.0