[PATCH v4 4/7] ata: libata: cleanup fua support detection

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

Move the detection of a device FUA support from
ata_scsiop_mode_sense()/ata_dev_supports_fua() to device scan time in
ata_dev_configure().

The function ata_dev_config_fua() is introduced to detect if a device
supports FUA and this support is indicated using the new device flag
ATA_DFLAG_FUA.

In order to blacklist known buggy devices, the horkage flag
ATA_HORKAGE_NO_FUA is introduced. Similarly to other horkage flags, the
libata.force= arguments "fua" and "nofua" are also introduced to allow
a user to control this horkage flag through the "force" libata
module parameter.

The ATA_DFLAG_FUA device flag is set only and only if all the following
conditions are met:
* libata.fua module parameter is set to 1
* The device supports the WRITE DMA FUA EXT command,
* The device is not marked with the ATA_HORKAGE_NO_FUA flag, either from
  the blacklist or set by the user with libata.force=nofua
* The device supports NCQ (while this is not mandated by the standards,
  this restriction is introduced to avoid problems with older non-NCQ
  devices).

Enabling or diabling libata FUA support for all devices can now also be
done using the "force=[no]fua" module parameter when libata.fua is set
to 1.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 .../admin-guide/kernel-parameters.txt         |  3 ++
 drivers/ata/libata-core.c                     | 30 ++++++++++++++++++-
 drivers/ata/libata-scsi.c                     | 30 ++-----------------
 include/linux/libata.h                        |  8 +++--
 4 files changed, 39 insertions(+), 32 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a465d5242774..f9724642c703 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2786,6 +2786,9 @@
 			* [no]setxfer: Indicate if transfer speed mode setting
 			  should be skipped.
 
+			* [no]fua: Disable or enable FUA (Force Unit Access)
+			  support for devices supporting this feature.
+
 			* dump_id: Dump IDENTIFY data.
 
 			* disable: Disable this device.
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6ee1cbac3ab0..30adae16efff 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2422,6 +2422,28 @@ static void ata_dev_config_chs(struct ata_device *dev)
 			     dev->heads, dev->sectors);
 }
 
+static void ata_dev_config_fua(struct ata_device *dev)
+{
+	/* Ignore FUA support if its use is disabled globally */
+	if (!libata_fua)
+		goto nofua;
+
+	/* Ignore devices without support for WRITE DMA FUA EXT */
+	if (!(dev->flags & ATA_DFLAG_LBA48) || !ata_id_has_fua(dev->id))
+		goto nofua;
+
+	/* Ignore known bad devices and devices that lack NCQ support */
+	if (!ata_ncq_supported(dev) || (dev->horkage & ATA_HORKAGE_NO_FUA))
+		goto nofua;
+
+	dev->flags |= ATA_DFLAG_FUA;
+
+	return;
+
+nofua:
+	dev->flags &= ~ATA_DFLAG_FUA;
+}
+
 static void ata_dev_config_devslp(struct ata_device *dev)
 {
 	u8 *sata_setting = dev->link->ap->sector_buf;
@@ -2510,7 +2532,8 @@ static void ata_dev_print_features(struct ata_device *dev)
 		return;
 
 	ata_dev_info(dev,
-		     "Features:%s%s%s%s%s%s\n",
+		     "Features:%s%s%s%s%s%s%s\n",
+		     dev->flags & ATA_DFLAG_FUA ? " FUA" : "",
 		     dev->flags & ATA_DFLAG_TRUSTED ? " Trust" : "",
 		     dev->flags & ATA_DFLAG_DA ? " Dev-Attention" : "",
 		     dev->flags & ATA_DFLAG_DEVSLP ? " Dev-Sleep" : "",
@@ -2671,6 +2694,7 @@ int ata_dev_configure(struct ata_device *dev)
 			ata_dev_config_chs(dev);
 		}
 
+		ata_dev_config_fua(dev);
 		ata_dev_config_devslp(dev);
 		ata_dev_config_sense_reporting(dev);
 		ata_dev_config_zac(dev);
@@ -4105,6 +4129,9 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
 	 */
 	{ "SATADOM-ML 3ME",		NULL,	ATA_HORKAGE_NO_LOG_DIR },
 
+	/* Buggy FUA */
+	{ "Maxtor",		"BANC1G10",	ATA_HORKAGE_NO_FUA },
+
 	/* End Marker */
 	{ }
 };
@@ -6216,6 +6243,7 @@ static const struct ata_force_param force_tbl[] __initconst = {
 	force_horkage_onoff(lpm,	ATA_HORKAGE_NOLPM),
 	force_horkage_onoff(setxfer,	ATA_HORKAGE_NOSETXFER),
 	force_horkage_on(dump_id,	ATA_HORKAGE_DUMP_ID),
+	force_horkage_onoff(fua,	ATA_HORKAGE_NO_FUA),
 
 	force_horkage_on(disable,	ATA_HORKAGE_DISABLE),
 };
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 4cb914103382..69948e2a8f6d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2240,30 +2240,6 @@ static unsigned int ata_msense_rw_recovery(u8 *buf, bool changeable)
 	return sizeof(def_rw_recovery_mpage);
 }
 
-/*
- * We can turn this into a real blacklist if it's needed, for now just
- * blacklist any Maxtor BANC1G10 revision firmware
- */
-static int ata_dev_supports_fua(u16 *id)
-{
-	unsigned char model[ATA_ID_PROD_LEN + 1], fw[ATA_ID_FW_REV_LEN + 1];
-
-	if (!libata_fua)
-		return 0;
-	if (!ata_id_has_fua(id))
-		return 0;
-
-	ata_id_c_string(id, model, ATA_ID_PROD, sizeof(model));
-	ata_id_c_string(id, fw, ATA_ID_FW_REV, sizeof(fw));
-
-	if (strcmp(model, "Maxtor"))
-		return 1;
-	if (strcmp(fw, "BANC1G10"))
-		return 1;
-
-	return 0; /* blacklisted */
-}
-
 /**
  *	ata_scsiop_mode_sense - Simulate MODE SENSE 6, 10 commands
  *	@args: device IDENTIFY data / SCSI command of interest.
@@ -2287,7 +2263,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 	};
 	u8 pg, spg;
 	unsigned int ebd, page_control, six_byte;
-	u8 dpofua, bp = 0xff;
+	u8 dpofua = 0, bp = 0xff;
 	u16 fp;
 
 	six_byte = (scsicmd[0] == MODE_SENSE);
@@ -2350,9 +2326,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 		goto invalid_fld;
 	}
 
-	dpofua = 0;
-	if (ata_dev_supports_fua(args->id) && (dev->flags & ATA_DFLAG_LBA48) &&
-	    (!(dev->flags & ATA_DFLAG_PIO) || dev->multi_count))
+	if (dev->flags & ATA_DFLAG_FUA)
 		dpofua = 1 << 4;
 
 	if (six_byte) {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 58651f565b36..d30c1288504d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -91,6 +91,7 @@ enum {
 	ATA_DFLAG_AN		= (1 << 7), /* AN configured */
 	ATA_DFLAG_TRUSTED	= (1 << 8), /* device supports trusted send/recv */
 	ATA_DFLAG_DMADIR	= (1 << 10), /* device requires DMADIR */
+	ATA_DFLAG_FUA		= (1 << 11), /* device supports FUA */
 	ATA_DFLAG_CFG_MASK	= (1 << 12) - 1,
 
 	ATA_DFLAG_PIO		= (1 << 12), /* device limited to PIO mode */
@@ -113,9 +114,9 @@ enum {
 	ATA_DFLAG_D_SENSE	= (1 << 29), /* Descriptor sense requested */
 	ATA_DFLAG_ZAC		= (1 << 30), /* ZAC device */
 
-	ATA_DFLAG_FEATURES_MASK	= ATA_DFLAG_TRUSTED | ATA_DFLAG_DA | \
-				  ATA_DFLAG_DEVSLP | ATA_DFLAG_NCQ_SEND_RECV | \
-				  ATA_DFLAG_NCQ_PRIO,
+	ATA_DFLAG_FEATURES_MASK	= (ATA_DFLAG_TRUSTED | ATA_DFLAG_DA |	\
+				   ATA_DFLAG_DEVSLP | ATA_DFLAG_NCQ_SEND_RECV | \
+				   ATA_DFLAG_NCQ_PRIO | ATA_DFLAG_FUA),
 
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */
@@ -381,6 +382,7 @@ enum {
 	ATA_HORKAGE_NO_NCQ_ON_ATI = (1 << 27),	/* Disable NCQ on ATI chipset */
 	ATA_HORKAGE_NO_ID_DEV_LOG = (1 << 28),	/* Identify device log missing */
 	ATA_HORKAGE_NO_LOG_DIR	= (1 << 29),	/* Do not read log directory */
+	ATA_HORKAGE_NO_FUA	= (1 << 30),	/* Do not use FUA */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */
-- 
2.38.1