ata: Enabling ATA Command Priorities
This patch checks to see if an ATA device supports NCQ command priorities.
If so and the user has specified an iocontext that indicates
IO_PRIO_CLASS_RT then we build a tf with a high priority command.
This is done to improve the tail latency of commands that are high
priority by passing priority to the device.
tj: Removed trivial ata_ncq_prio_enabled() and open-coded the test.
Signed-off-by: Adam Manzanares <adam.manzanares@hgst.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/include/linux/ata.h b/include/linux/ata.h
index fdb1803..af6859b 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -348,6 +348,7 @@
ATA_LOG_DEVSLP_DETO = 0x01,
ATA_LOG_DEVSLP_VALID = 0x07,
ATA_LOG_DEVSLP_VALID_MASK = 0x80,
+ ATA_LOG_NCQ_PRIO_OFFSET = 0x09,
/* NCQ send and receive log */
ATA_LOG_NCQ_SEND_RECV_SUBCMDS_OFFSET = 0x00,
@@ -940,6 +941,11 @@
return id[ATA_ID_SATA_CAPABILITY_2] & BIT(5);
}
+static inline bool ata_id_has_ncq_prio(const u16 *id)
+{
+ return id[ATA_ID_SATA_CAPABILITY] & BIT(12);
+}
+
static inline bool ata_id_has_trim(const u16 *id)
{
if (ata_id_major_version(id) >= 7 &&