libata: cleanup NCQ priority handling

The ata device flag ATA_DFLAG_NCQ_PRIO indicates if a device supports
the NCQ Priority feature while the ATA_DFLAG_NCQ_PRIO_ENABLE device
flag indicates if the feature is enabled. Enabling NCQ priority use is
controlled by the user through the device sysfs attribute
ncq_prio_enable. As a result, the ATA_DFLAG_NCQ_PRIO flag should not be
cleared when ATA_DFLAG_NCQ_PRIO_ENABLE is not set as the device still
supports the feature even after the user disables it. This leads to the
following cleanups:
- In ata_build_rw_tf(), set a command high priority bit based on the
  ATA_DFLAG_NCQ_PRIO_ENABLE flag, not on the ATA_DFLAG_NCQ flag. That
  is, set a command high priority only if the user enabled NCQ priority
  use.
- In ata_dev_config_ncq_prio(), ATA_DFLAG_NCQ_PRIO should not be cleared
  if ATA_DFLAG_NCQ_PRIO_ENABLE is not set. If the device does not
  support NCQ priority, both ATA_DFLAG_NCQ_PRIO and
  ATA_DFLAG_NCQ_PRIO_ENABLE must be cleared.

With the above ata_dev_config_ncq_prio() change, ATA_DFLAG_NCQ_PRIO flag
is set on device scan and revalidation. There is no need to trigger a
device revalidation in ata_ncq_prio_enable_store() when the user enables
the use of NCQ priority. Remove the revalidation code from that funciton
to simplify it. Also change the return value from -EIO to -EINVAL when a
user tries to enable NCQ priority for a device that does not support
this feature.  While at it, also simplify ata_ncq_prio_enable_show().

Overall, there is no functional change introduced by this patch.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210816014456.2191776-7-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index f600ea16a92c5f9d3bef80e0161be392d39a1d41..f285a2bc87996cf23451746231f5cf39017c4a0c 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -712,11 +712,9 @@ 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 (class == IOPRIO_CLASS_RT)
-                               tf->hob_nsect |= ATA_PRIO_HIGH <<
-                                                ATA_SHIFT_PRIO;
-               }
+               if (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE &&
+                   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;
 
@@ -2178,11 +2176,6 @@ static void ata_dev_config_ncq_prio(struct ata_device *dev)
        struct ata_port *ap = dev->link->ap;
        unsigned int err_mask;
 
-       if (!(dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE)) {
-               dev->flags &= ~ATA_DFLAG_NCQ_PRIO;
-               return;
-       }
-
        err_mask = ata_read_log_page(dev,
                                     ATA_LOG_IDENTIFY_DEVICE,
                                     ATA_LOG_SATA_SETTINGS,
@@ -2190,18 +2183,21 @@ static void ata_dev_config_ncq_prio(struct ata_device *dev)
                                     1);
        if (err_mask) {
                ata_dev_dbg(dev,
-                           "failed to get Identify Device data, Emask 0x%x\n",
+                           "failed to get SATA settings log, Emask 0x%x\n",
                            err_mask);
-               return;
+               goto not_supported;
        }
 
-       if (ap->sector_buf[ATA_LOG_NCQ_PRIO_OFFSET] & BIT(3)) {
-               dev->flags |= ATA_DFLAG_NCQ_PRIO;
-       } else {
-               dev->flags &= ~ATA_DFLAG_NCQ_PRIO;
-               ata_dev_dbg(dev, "SATA page does not support priority\n");
-       }
+       if (!(ap->sector_buf[ATA_LOG_NCQ_PRIO_OFFSET] & BIT(3)))
+               goto not_supported;
+
+       dev->flags |= ATA_DFLAG_NCQ_PRIO;
+
+       return;
 
+not_supported:
+       dev->flags &= ~ATA_DFLAG_NCQ_PRIO_ENABLE;
+       dev->flags &= ~ATA_DFLAG_NCQ_PRIO;
 }
 
 static int ata_dev_config_ncq(struct ata_device *dev,

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index 8adeab76dd382b9361af000e80d7a2d469491151..dc397ebda08952a46a8c718e4cd612e38d29e87d 100644 (file)
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -839,23 +839,17 @@ static ssize_t ata_ncq_prio_enable_show(struct device *device,
                                        char *buf)
 {
        struct scsi_device *sdev = to_scsi_device(device);
-       struct ata_port *ap;
+       struct ata_port *ap = ata_shost_to_port(sdev->host);
        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) {
+       if (!dev)
                rc = -ENODEV;
-               goto unlock;
-       }
-
-       ncq_prio_enable = dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE;
-
-unlock:
+       else
+               ncq_prio_enable = dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLE;
        spin_unlock_irq(ap->lock);
 
        return rc ? rc : snprintf(buf, 20, "%u\n", ncq_prio_enable);
@@ -869,7 +863,7 @@ static ssize_t ata_ncq_prio_enable_store(struct device *device,
        struct ata_port *ap;
        struct ata_device *dev;
        long int input;
-       int rc;
+       int rc = 0;
 
        rc = kstrtol(buf, 10, &input);
        if (rc)
@@ -883,27 +877,20 @@ static ssize_t ata_ncq_prio_enable_store(struct device *device,
                return  -ENODEV;
 
        spin_lock_irq(ap->lock);
+
+       if (!(dev->flags & ATA_DFLAG_NCQ_PRIO)) {
+               rc = -EINVAL;
+               goto unlock;
+       }
+
        if (input)
                dev->flags |= ATA_DFLAG_NCQ_PRIO_ENABLE;
        else
                dev->flags &= ~ATA_DFLAG_NCQ_PRIO_ENABLE;
 
-       dev->link->eh_info.action |= ATA_EH_REVALIDATE;
-       dev->link->eh_info.flags |= ATA_EHI_QUIET;
-       ata_port_schedule_eh(ap);
+unlock:
        spin_unlock_irq(ap->lock);
 
-       ata_port_wait_eh(ap);
-
-       if (input) {
-               spin_lock_irq(ap->lock);
-               if (!(dev->flags & ATA_DFLAG_NCQ_PRIO)) {
-                       dev->flags &= ~ATA_DFLAG_NCQ_PRIO_ENABLE;
-                       rc = -EIO;
-               }
-               spin_unlock_irq(ap->lock);
-       }
-
        return rc ? rc : len;
 }