scsi: mpt3sas: Recognize and act on iopriority info

This patch adds support for request iopriority handling in the mpt3sas
layer. This works only when a ATA device is behind the SATL. The ATA
device also has to indicate that it supports command priorities in the
identify information that is pulled from the SATL.

Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
Acked-by: Sreekanth Reddy <Sreekanth.Reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 80 insertions, 3 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index 8de0eda8cd00..394fe1338d09 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -402,6 +402,9 @@ struct MPT3SAS_DEVICE {
         u8      block;
         u8      tlr_snoop_check;
         u8      ignore_delay_remove;
+        /* Iopriority Command Handling */
+        u8      ncq_prio_enable;
+
 };
 
 #define MPT3_CMD_NOT_USED       0x8000  /* free */
@@ -1458,4 +1461,7 @@ mpt3sas_setup_direct_io(struct MPT3SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
         struct _raid_device *raid_device, Mpi2SCSIIORequest_t *mpi_request,
         u16 smid);
 
+/* NCQ Prio Handling Check */
+bool scsih_ncq_prio_supp(struct scsi_device *sdev);
+
 #endif /* MPT3SAS_BASE_H_INCLUDED */
diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index 050bd788ad02..95f0f24bac05 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -3325,8 +3325,6 @@ static DEVICE_ATTR(diag_trigger_mpi, S_IRUGO | S_IWUSR,
 
 /*********** diagnostic trigger suppport *** END ****************************/
 
-
-
 /*****************************************/
 
 struct device_attribute *mpt3sas_host_attrs[] = {
@@ -3402,9 +3400,50 @@ _ctl_device_handle_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR(sas_device_handle, S_IRUGO, _ctl_device_handle_show, NULL);
 
+/**
+ * _ctl_device_ncq_io_prio_show - send prioritized io commands to device
+ * @dev - pointer to embedded device
+ * @buf - the buffer returned
+ *
+ * A sysfs 'read/write' sdev attribute, only works with SATA
+ */
+static ssize_t
+_ctl_device_ncq_prio_enable_show(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+        struct scsi_device *sdev = to_scsi_device(dev);
+        struct MPT3SAS_DEVICE *sas_device_priv_data = sdev->hostdata;
+
+        return snprintf(buf, PAGE_SIZE, "%d\n",
+                        sas_device_priv_data->ncq_prio_enable);
+}
+
+static ssize_t
+_ctl_device_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 MPT3SAS_DEVICE *sas_device_priv_data = sdev->hostdata;
+        bool ncq_prio_enable = 0;
+
+        if (kstrtobool(buf, &ncq_prio_enable))
+                return -EINVAL;
+
+        if (!scsih_ncq_prio_supp(sdev))
+                return -EINVAL;
+
+        sas_device_priv_data->ncq_prio_enable = ncq_prio_enable;
+        return strlen(buf);
+}
+static DEVICE_ATTR(sas_ncq_prio_enable, S_IRUGO | S_IWUSR,
+                   _ctl_device_ncq_prio_enable_show,
+                   _ctl_device_ncq_prio_enable_store);
+
 struct device_attribute *mpt3sas_dev_attrs[] = {
         &dev_attr_sas_address,
         &dev_attr_sas_device_handle,
+        &dev_attr_sas_ncq_prio_enable,
         NULL,
 };
 
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 5c8f75247d73..b5c966e319d3 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -4053,6 +4053,8 @@ scsih_qcmd(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
         struct MPT3SAS_DEVICE *sas_device_priv_data;
         struct MPT3SAS_TARGET *sas_target_priv_data;
         struct _raid_device *raid_device;
+        struct request *rq = scmd->request;
+        int class;
         Mpi2SCSIIORequest_t *mpi_request;
         u32 mpi_control;
         u16 smid;
@@ -4115,7 +4117,12 @@ scsih_qcmd(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
 
         /* set tags */
         mpi_control |= MPI2_SCSIIO_CONTROL_SIMPLEQ;
-
+        /* NCQ Prio supported, make sure control indicated high priority */
+        if (sas_device_priv_data->ncq_prio_enable) {
+                class = IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
+                if (class == IOPRIO_CLASS_RT)
+                        mpi_control |= 1 << MPI2_SCSIIO_CONTROL_CMDPRI_SHIFT;
+        }
         /* Make sure Device is not raid volume.
          * We do not expose raid functionality to upper layer for warpdrive.
          */
@@ -9099,6 +9106,31 @@ scsih_pci_mmio_enabled(struct pci_dev *pdev)
         return PCI_ERS_RESULT_RECOVERED;
 }
 
+/**
+ * scsih__ncq_prio_supp - Check for NCQ command priority support
+ * @sdev: scsi device struct
+ *
+ * This is called when a user indicates they would like to enable
+ * ncq command priorities. This works only on SATA devices.
+ */
+bool scsih_ncq_prio_supp(struct scsi_device *sdev)
+{
+        unsigned char *buf;
+        bool ncq_prio_supp = false;
+
+        if (!scsi_device_supports_vpd(sdev))
+                return ncq_prio_supp;
+
+        buf = kmalloc(SCSI_VPD_PG_LEN, GFP_KERNEL);
+        if (!buf)
+                return ncq_prio_supp;
+
+        if (!scsi_get_vpd_page(sdev, 0x89, buf, SCSI_VPD_PG_LEN))
+                ncq_prio_supp = (buf[213] >> 4) & 1;
+
+        kfree(buf);
+        return ncq_prio_supp;
+}
 /*
  * The pci device ids are defined in mpi/mpi2_cnfg.h.
  */