diff options
author | Adam Manzanares <adam.manzanares@hgst.com> | 2016-10-17 11:27:29 -0700 |
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committer | Tejun Heo <tj@kernel.org> | 2016-10-19 14:34:36 -0400 |
commit | 8e061784b51ec4a4efed0deaafb5bd9725bf5b06 (patch) | |
tree | 30d253d6d6a214f6514484bfe1d2c3b178fdf62e /drivers/ata/libata-core.c | |
parent | 5dc8b362a2374d007bc0db649b7ab6a79dd32bda (diff) | |
download | linux-8e061784b51ec4a4efed0deaafb5bd9725bf5b06.tar.gz |
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>
Diffstat (limited to 'drivers/ata/libata-core.c')
-rw-r--r-- | drivers/ata/libata-core.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 223a770f78f3..8346faf63337 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -739,6 +739,7 @@ u64 ata_tf_read_block(const struct ata_taskfile *tf, struct ata_device *dev) * @n_block: Number of blocks * @tf_flags: RW/FUA etc... * @tag: tag + * @class: IO priority class * * LOCKING: * None. @@ -753,7 +754,7 @@ u64 ata_tf_read_block(const struct ata_taskfile *tf, struct ata_device *dev) */ int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev, u64 block, u32 n_block, unsigned int tf_flags, - unsigned int tag) + unsigned int tag, int class) { tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; tf->flags |= tf_flags; @@ -785,6 +786,12 @@ int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev, tf->device = ATA_LBA; if (tf->flags & ATA_TFLAG_FUA) tf->device |= 1 << 7; + + if (dev->flags & ATA_DFLAG_NCQ_PRIO) { + if (class == IOPRIO_CLASS_RT) + tf->hob_nsect |= ATA_PRIO_HIGH << + ATA_SHIFT_PRIO; + } } else if (dev->flags & ATA_DFLAG_LBA) { tf->flags |= ATA_TFLAG_LBA; @@ -2156,6 +2163,30 @@ static void ata_dev_config_ncq_non_data(struct ata_device *dev) } } +static void ata_dev_config_ncq_prio(struct ata_device *dev) +{ + struct ata_port *ap = dev->link->ap; + unsigned int err_mask; + + err_mask = ata_read_log_page(dev, + ATA_LOG_SATA_ID_DEV_DATA, + ATA_LOG_SATA_SETTINGS, + ap->sector_buf, + 1); + if (err_mask) { + ata_dev_dbg(dev, + "failed to get Identify Device data, Emask 0x%x\n", + err_mask); + return; + } + + if (ap->sector_buf[ATA_LOG_NCQ_PRIO_OFFSET] & BIT(3)) + dev->flags |= ATA_DFLAG_NCQ_PRIO; + else + ata_dev_dbg(dev, "SATA page does not support priority\n"); + +} + static int ata_dev_config_ncq(struct ata_device *dev, char *desc, size_t desc_sz) { @@ -2205,6 +2236,8 @@ static int ata_dev_config_ncq(struct ata_device *dev, ata_dev_config_ncq_send_recv(dev); if (ata_id_has_ncq_non_data(dev->id)) ata_dev_config_ncq_non_data(dev); + if (ata_id_has_ncq_prio(dev->id)) + ata_dev_config_ncq_prio(dev); } return 0; |