scsi: mpi3mr: Fix ATA NCQ priority support

The function mpi3mr_qcmd() of the mpi3mr driver is able to indicate to
the HBA if a read or write command directed at an ATA device should be
translated to an NCQ read/write command with the high prioiryt bit set
when the request uses the RT priority class and the user has enabled NCQ
priority through sysfs.

However, unlike the mpt3sas driver, the mpi3mr driver does not define
the sas_ncq_prio_supported and sas_ncq_prio_enable sysfs attributes, so
the ncq_prio_enable field of struct mpi3mr_sdev_priv_data is never
actually set and NCQ Priority cannot ever be used.

Fix this by defining these missing atributes to allow a user to check if
an ATA device supports NCQ priority and to enable/disable the use of NCQ
priority. To do this, lift the function scsih_ncq_prio_supp() out of the
mpt3sas driver and make it the generic SCSI SAS transport function
sas_ata_ncq_prio_supported(). Nothing in that function is hardware
specific, so this function can be used in both the mpt3sas driver and
the mpi3mr driver.

Reported-by: Scott McCoy <scott.mccoy@wdc.com>
Fixes: 023ab2a9b4ed ("scsi: mpi3mr: Add support for queue command processing")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240611083435.92961-1-dlemoal@kernel.org
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/scsi/mpi3mr/mpi3mr_app.c b/drivers/scsi/mpi3mr/mpi3mr_app.c
index 1638109a68a0..cd261b48eb46 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_app.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_app.c
@@ -2163,10 +2163,72 @@ persistent_id_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(persistent_id);
 
+/**
+ * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
+ * @dev: pointer to embedded device
+ * @attr: sas_ncq_prio_supported attribute descriptor
+ * @buf: the buffer returned
+ *
+ * A sysfs 'read-only' sdev attribute, only works with SATA devices
+ */
+static ssize_t
+sas_ncq_prio_supported_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+
+	return sysfs_emit(buf, "%d\n", sas_ata_ncq_prio_supported(sdev));
+}
+static DEVICE_ATTR_RO(sas_ncq_prio_supported);
+
+/**
+ * sas_ncq_prio_enable_show - send prioritized io commands to device
+ * @dev: pointer to embedded device
+ * @attr: sas_ncq_prio_enable attribute descriptor
+ * @buf: the buffer returned
+ *
+ * A sysfs 'read/write' sdev attribute, only works with SATA devices
+ */
+static ssize_t
+sas_ncq_prio_enable_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct mpi3mr_sdev_priv_data *sdev_priv_data =  sdev->hostdata;
+
+	if (!sdev_priv_data)
+		return 0;
+
+	return sysfs_emit(buf, "%d\n", sdev_priv_data->ncq_prio_enable);
+}
+
+static ssize_t
+sas_ncq_prio_enable_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct mpi3mr_sdev_priv_data *sdev_priv_data =  sdev->hostdata;
+	bool ncq_prio_enable = 0;
+
+	if (kstrtobool(buf, &ncq_prio_enable))
+		return -EINVAL;
+
+	if (!sas_ata_ncq_prio_supported(sdev))
+		return -EINVAL;
+
+	sdev_priv_data->ncq_prio_enable = ncq_prio_enable;
+
+	return strlen(buf);
+}
+static DEVICE_ATTR_RW(sas_ncq_prio_enable);
+
 static struct attribute *mpi3mr_dev_attrs[] = {
 	&dev_attr_sas_address.attr,
 	&dev_attr_device_handle.attr,
 	&dev_attr_persistent_id.attr,
+	&dev_attr_sas_ncq_prio_supported.attr,
+	&dev_attr_sas_ncq_prio_enable.attr,
 	NULL,
 };