[PATCH 2/3] scsi: libsas: Define NCQ Priority sysfs attributes for SATA devices

[Igor Pylypiv <ipylypiv@google.com>]

Libata sysfs attributes cannot be used for libsas managed SATA devices
because the ata_port location is different for libsas.

Defined sysfs attributes (visible for SATA devices only):
- /sys/block/*/device/sas_ncq_prio_enable
- /sys/block/*/device/sas_ncq_prio_supported

The newly defined attributes will pass the correct ata_port to libata
helper functions.

Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
Reviewed-by: TJ Adams <tadamsjr@google.com>
---
 drivers/scsi/libsas/sas_ata.c | 87 +++++++++++++++++++++++++++++++++++
 include/scsi/sas_ata.h        |  6 +++
 2 files changed, 93 insertions(+)

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 12e2653846e3..e0b19eee09b5 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -964,3 +964,90 @@ int sas_execute_ata_cmd(struct domain_device *device, u8 *fis, int force_phy_id)
 			       force_phy_id, &tmf_task);
 }
 EXPORT_SYMBOL_GPL(sas_execute_ata_cmd);
+
+static ssize_t sas_ncq_prio_supported_show(struct device *device,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(device);
+	struct domain_device *ddev = sdev_to_domain_dev(sdev);
+	int res;
+
+	// This attribute shall be visible for SATA devices only
+	if (WARN_ON(!dev_is_sata(ddev)))
+		return -EINVAL;
+
+	res = ata_ncq_prio_supported(ddev->sata_dev.ap, sdev);
+	if (res < 0)
+		return res;
+
+	return sysfs_emit(buf, "%u\n", res);
+}
+static DEVICE_ATTR_RO(sas_ncq_prio_supported);
+
+static ssize_t sas_ncq_prio_enable_show(struct device *device,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(device);
+	struct domain_device *ddev = sdev_to_domain_dev(sdev);
+	int res;
+
+	// This attribute shall be visible for SATA devices only
+	if (WARN_ON(!dev_is_sata(ddev)))
+		return -EINVAL;
+
+	res = ata_ncq_prio_enabled(ddev->sata_dev.ap, sdev);
+	if (res < 0)
+		return res;
+
+	return sysfs_emit(buf, "%u\n", res);
+}
+
+static ssize_t sas_ncq_prio_enable_store(struct device *device,
+					 struct device_attribute *attr,
+					 const char *buf, size_t len)
+{
+	struct scsi_device *sdev = to_scsi_device(device);
+	struct domain_device *ddev = sdev_to_domain_dev(sdev);
+	long input;
+	int res;
+
+	// This attribute shall be visible for SATA devices only
+	if (WARN_ON(!dev_is_sata(ddev)))
+		return -EINVAL;
+
+	res = kstrtol(buf, 10, &input);
+	if (res)
+		return res;
+	if ((input < 0) || (input > 1))
+		return -EINVAL;
+
+	return ata_ncq_prio_enable(ddev->sata_dev.ap, sdev, input) ? : len;
+}
+static DEVICE_ATTR_RW(sas_ncq_prio_enable);
+
+static struct attribute *sas_ata_sdev_attrs[] = {
+	&dev_attr_sas_ncq_prio_supported.attr,
+	&dev_attr_sas_ncq_prio_enable.attr,
+	NULL
+};
+
+static umode_t sas_ata_attr_is_visible(struct kobject *kobj,
+				       struct attribute *attr, int i)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct domain_device *ddev = sdev_to_domain_dev(sdev);
+
+	if (!dev_is_sata(ddev))
+		return 0;
+
+	return attr->mode;
+}
+
+const struct attribute_group sas_ata_sdev_attr_group = {
+	.attrs = sas_ata_sdev_attrs,
+	.is_visible = sas_ata_attr_is_visible,
+};
+EXPORT_SYMBOL_GPL(sas_ata_sdev_attr_group);
diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
index 2f8c719840a6..cded782fdf33 100644
--- a/include/scsi/sas_ata.h
+++ b/include/scsi/sas_ata.h
@@ -39,6 +39,8 @@ int smp_ata_check_ready_type(struct ata_link *link);
 int sas_discover_sata(struct domain_device *dev);
 int sas_ata_add_dev(struct domain_device *parent, struct ex_phy *phy,
 		    struct domain_device *child, int phy_id);
+
+extern const struct attribute_group sas_ata_sdev_attr_group;
 #else
 
 static inline void sas_ata_disabled_notice(void)
@@ -123,6 +125,10 @@ static inline int sas_ata_add_dev(struct domain_device *parent, struct ex_phy *p
 	sas_ata_disabled_notice();
 	return -ENODEV;
 }
+
+static const struct attribute_group sas_ata_sdev_attr_group = {
+	.attrs = NULL,
+};
 #endif
 
 #endif /* _SAS_ATA_H_ */
-- 
2.44.0.278.ge034bb2e1d-goog