[PATCH v4 4/4] ata: ATA Command Priority Disabled By Default

Adam Manzanares
2016-10-13T19:53:53Z

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

Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
---
drivers/ata/libahci.c | 1 +
drivers/ata/libata-core.c | 2 +-
drivers/ata/libata-scsi.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/libata.h | 8 ++++++
4 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index dcf2c72..383adf7 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_enable_prio,
NULL
};
EXPORT_SYMBOL_GPL(ahci_sdev_attrs);
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 181b530..d0cf987 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -787,7 +787,7 @@ int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
if (tf->flags & ATA_TFLAG_FUA)
tf->device |= 1 << 7;

- if (ata_ncq_prio_enabled(dev)) {
+ if (ata_ncq_prio_enabled(dev) && ata_prio_enabled(dev)) {
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 18629e8..10ba118 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_enable_prio_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;
+ int rc = 0;
+ int enable_prio;
+
+ 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;
+ }
+
+ enable_prio = ata_prio_enabled(dev);
+
+unlock:
+ spin_unlock_irq(ap->lock);
+
+ return rc ? rc : snprintf(buf, 20, "%u\n", enable_prio);
+}
+
+static ssize_t ata_enable_prio_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_ENABLE_PRIO;
+ else
+ dev->flags &= ~ATA_DFLAG_ENABLE_PRIO;
+
+unlock:
+ spin_unlock_irqrestore(ap->lock, flags);
+
+ return rc ? rc : len;
+}
+
+DEVICE_ATTR(enable_prio, S_IRUGO | S_IWUSR,
+ ata_enable_prio_show, ata_enable_prio_store);
+EXPORT_SYMBOL_GPL(dev_attr_enable_prio);
+
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_enable_prio,
NULL
};
EXPORT_SYMBOL_GPL(ata_common_sdev_attrs);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 244f261..c8acb16 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -166,6 +166,7 @@ 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_ENABLE_PRIO = (1 << 21), /* User enable device priority */
ATA_DFLAG_INIT_MASK = (1 << 24) - 1,

ATA_DFLAG_DETACH = (1 << 24),
@@ -544,6 +545,7 @@ 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_enable_prio;
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;
@@ -1627,6 +1629,12 @@ static inline int ata_ncq_prio_enabled(struct ata_device *dev)
return (dev->flags & ATA_DFLAG_NCQ_PRIO) == ATA_DFLAG_NCQ_PRIO;
}

+static inline int ata_prio_enabled(struct ata_device *dev)
+{
+ return ((dev->flags & ATA_DFLAG_ENABLE_PRIO) ==
+ ATA_DFLAG_ENABLE_PRIO);
+}
+
static inline bool ata_fpdma_dsm_supported(struct ata_device *dev)
{
return (dev->flags & ATA_DFLAG_NCQ_SEND_RECV) &&
--
2.1.4