[PATCH 2/2] ata: ATA Command Priority Disabled By Default

From: Adam Manzanares
Date: Mon Oct 17 2016 - 14:27:30 EST


Add a sysfs entry to turn on priority information being passed
to a ATA device. By default this feature is turned off.

This patch depends on ata: Enabling ATA Command Priorities

tj: Renamed ncq_prio_on to ncq_prio_enable and removed trivial
ata_ncq_prio_on() and open-coded the test.

Signed-off-by: Adam Manzanares <adam.manzanares@xxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
drivers/ata/libahci.c | 1 +
drivers/ata/libata-core.c | 3 ++-
drivers/ata/libata-scsi.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/libata.h | 2 ++
4 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 0d028ea..ee7db31 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -140,6 +140,7 @@ EXPORT_SYMBOL_GPL(ahci_shost_attrs);
struct device_attribute *ahci_sdev_attrs[] = {
&dev_attr_sw_activity,
&dev_attr_unload_heads,
+ &dev_attr_ncq_prio_enable,
NULL
};
EXPORT_SYMBOL_GPL(ahci_sdev_attrs);
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 8346faf..b294339 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -787,7 +787,8 @@ int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
if (tf->flags & ATA_TFLAG_FUA)
tf->device |= 1 << 7;

- if (dev->flags & ATA_DFLAG_NCQ_PRIO) {
+ if ((dev->flags & ATA_DFLAG_NCQ_PRIO) &&
+ (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE)) {
if (class == IOPRIO_CLASS_RT)
tf->hob_nsect |= ATA_PRIO_HIGH <<
ATA_SHIFT_PRIO;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 2bccc3c..87597a3 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -271,6 +271,73 @@ DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
ata_scsi_park_show, ata_scsi_park_store);
EXPORT_SYMBOL_GPL(dev_attr_unload_heads);

+static ssize_t ata_ncq_prio_enable_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct scsi_device *sdev = to_scsi_device(device);
+ struct ata_port *ap;
+ struct ata_device *dev;
+ bool ncq_prio_enable;
+ int rc = 0;
+
+ ap = ata_shost_to_port(sdev->host);
+
+ spin_lock_irq(ap->lock);
+ dev = ata_scsi_find_dev(ap, sdev);
+ if (!dev) {
+ rc = -ENODEV;
+ goto unlock;
+ }
+
+ ncq_prio_enable = dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE;
+
+unlock:
+ spin_unlock_irq(ap->lock);
+
+ return rc ? rc : snprintf(buf, 20, "%u\n", ncq_prio_enable);
+}
+
+static ssize_t ata_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 ata_port *ap;
+ struct ata_device *dev;
+ long int input;
+ unsigned long flags;
+ int rc;
+
+ rc = kstrtol(buf, 10, &input);
+ if (rc)
+ return rc;
+ if ((input < 0) || (input > 1))
+ return -EINVAL;
+
+ ap = ata_shost_to_port(sdev->host);
+
+ spin_lock_irqsave(ap->lock, flags);
+ dev = ata_scsi_find_dev(ap, sdev);
+ if (unlikely(!dev)) {
+ rc = -ENODEV;
+ goto unlock;
+ }
+
+ if (input)
+ dev->flags |= ATA_DFLAG_NCQ_PRIO_ENABLE;
+ else
+ dev->flags &= ~ATA_DFLAG_NCQ_PRIO_ENABLE;
+
+unlock:
+ spin_unlock_irqrestore(ap->lock, flags);
+
+ return rc ? rc : len;
+}
+
+DEVICE_ATTR(ncq_prio_enable, S_IRUGO | S_IWUSR,
+ ata_ncq_prio_enable_show, ata_ncq_prio_enable_store);
+EXPORT_SYMBOL_GPL(dev_attr_ncq_prio_enable);
+
void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
u8 sk, u8 asc, u8 ascq)
{
@@ -402,6 +469,7 @@ EXPORT_SYMBOL_GPL(dev_attr_sw_activity);

struct device_attribute *ata_common_sdev_attrs[] = {
&dev_attr_unload_heads,
+ &dev_attr_ncq_prio_enable,
NULL
};
EXPORT_SYMBOL_GPL(ata_common_sdev_attrs);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 90b69a6..c170be5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -167,6 +167,7 @@ enum {
ATA_DFLAG_UNLOCK_HPA = (1 << 18), /* unlock HPA */
ATA_DFLAG_NCQ_SEND_RECV = (1 << 19), /* device supports NCQ SEND and RECV */
ATA_DFLAG_NCQ_PRIO = (1 << 20), /* device supports NCQ priority */
+ ATA_DFLAG_NCQ_PRIO_ENABLE = (1 << 21), /* Priority cmds sent to dev */
ATA_DFLAG_INIT_MASK = (1 << 24) - 1,

ATA_DFLAG_DETACH = (1 << 24),
@@ -545,6 +546,7 @@ typedef void (*ata_postreset_fn_t)(struct ata_link *link, unsigned int *classes)

extern struct device_attribute dev_attr_link_power_management_policy;
extern struct device_attribute dev_attr_unload_heads;
+extern struct device_attribute dev_attr_ncq_prio_enable;
extern struct device_attribute dev_attr_em_message_type;
extern struct device_attribute dev_attr_em_message;
extern struct device_attribute dev_attr_sw_activity;
--
2.7.4