Re: [PATCH 1/3] ata: libata-sata: Factor out NCQ Priority configuration helpers

Damien Le Moal
2024-03-01T12:16:47Z

On 2024/02/29 17:37, Igor Pylypiv wrote:
> Export libata NCQ Priority configuration helpers to be reused
> for libsas managed SATA devices.
>
> Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
> Reviewed-by: TJ Adams <tadamsjr@google.com>

Please drop this tag as the email signaling the review was not sent to the
list/in-reply to this email. The name of the reviewer should also be fully
spelled out. Same comment for the other 2 patches as they also have this review tag.

> ---
> drivers/ata/libata-sata.c | 130 +++++++++++++++++++++++++-------------
> include/linux/libata.h | 4 ++
> 2 files changed, 90 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
> index 0fb1934875f2..9c6c69d7feab 100644
> --- a/drivers/ata/libata-sata.c
> +++ b/drivers/ata/libata-sata.c
> @@ -848,80 +848,104 @@ DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
> ata_scsi_lpm_show, ata_scsi_lpm_store);
> EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);
>
> +/**
> + * ata_ncq_prio_supported - Check if device supports NCQ Priority
> + * @ap: ATA port of the target device
> + * @sdev: SCSI device
> + *
> + * Helper to check if device supports NCQ Priority feature,
> + * usable with both libsas and libata.
> + */
> +int ata_ncq_prio_supported(struct ata_port *ap, struct scsi_device *sdev)
> +{
> + struct ata_device *dev;
> + unsigned long flags;
> + int rc;
> +
> + spin_lock_irqsave(ap->lock, flags);
> + dev = ata_scsi_find_dev(ap, sdev);
> + rc = dev ? !!(dev->flags & ATA_DFLAG_NCQ_PRIO) : -ENODEV;

Please expand this to make it more readable:

if (!dev)
rc = -ENODEV;
else
rc = !!(dev->flags & ATA_DFLAG_NCQ_PRIO);

> + spin_unlock_irqrestore(ap->lock, flags);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(ata_ncq_prio_supported);
> +
> static ssize_t ata_ncq_prio_supported_show(struct device *device,
> struct device_attribute *attr,
> char *buf)
> {
> struct scsi_device *sdev = to_scsi_device(device);
> struct ata_port *ap = ata_shost_to_port(sdev->host);
> - struct ata_device *dev;
> - bool ncq_prio_supported;
> - int rc = 0;
> -
> - spin_lock_irq(ap->lock);
> - dev = ata_scsi_find_dev(ap, sdev);
> - if (!dev)
> - rc = -ENODEV;
> - else
> - ncq_prio_supported = dev->flags & ATA_DFLAG_NCQ_PRIO;
> - spin_unlock_irq(ap->lock);
> + int rc = ata_ncq_prio_supported(ap, sdev);
>
> - return rc ? rc : sysfs_emit(buf, "%u\n", ncq_prio_supported);
> + return (rc < 0) ? rc : sysfs_emit(buf, "%u\n", rc);

Same here, please expand:

if (rc < 0)
return rc;
return sysfs_emit(buf, "%d\n", rc);

And please not the change %u -> %d

> }
> -

whiteline change. Please keep the white line.

> DEVICE_ATTR(ncq_prio_supported, S_IRUGO, ata_ncq_prio_supported_show, NULL);
> EXPORT_SYMBOL_GPL(dev_attr_ncq_prio_supported);
>
> +/**
> + * ata_ncq_prio_enabled - Check if NCQ Priority is enabled
> + * @ap: ATA port of the target device
> + * @sdev: SCSI device
> + *
> + * Helper to check if NCQ Priority feature is enabled,
> + * usable with both libsas and libata.
> + */
> +int ata_ncq_prio_enabled(struct ata_port *ap, struct scsi_device *sdev)
> +{
> + struct ata_device *dev;
> + unsigned long flags;
> + int rc;
> +
> + spin_lock_irqsave(ap->lock, flags);
> + dev = ata_scsi_find_dev(ap, sdev);
> + rc = dev ? !!(dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED) : -ENODEV;

same comment as above. Please expand.

> + spin_unlock_irqrestore(ap->lock, flags);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(ata_ncq_prio_enabled);
> +
> 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 = ata_shost_to_port(sdev->host);
> - struct ata_device *dev;
> - bool ncq_prio_enable;
> - int rc = 0;
> -
> - spin_lock_irq(ap->lock);
> - dev = ata_scsi_find_dev(ap, sdev);
> - if (!dev)
> - rc = -ENODEV;
> - else
> - ncq_prio_enable = dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED;
> - spin_unlock_irq(ap->lock);
> + int rc = ata_ncq_prio_enabled(ap, sdev);
>
> - return rc ? rc : sysfs_emit(buf, "%u\n", ncq_prio_enable);
> + return (rc < 0) ? rc : sysfs_emit(buf, "%u\n", rc);

same comment as above.

> }
>
> -static ssize_t ata_ncq_prio_enable_store(struct device *device,
> - struct device_attribute *attr,
> - const char *buf, size_t len)
> +/**
> + * ata_ncq_prio_enable - Enable/disable NCQ Priority
> + * @ap: ATA port of the target device
> + * @sdev: SCSI device
> + * @enable: true - enable NCQ Priority, false - disable NCQ Priority
> + *
> + * Helper to enable/disable NCQ Priority feature, usable with both
> + * libsas and libata.
> + */
> +int ata_ncq_prio_enable(struct ata_port *ap, struct scsi_device *sdev,
> + bool enable)
> {
> - struct scsi_device *sdev = to_scsi_device(device);
> - struct ata_port *ap;
> struct ata_device *dev;
> - long int input;
> + unsigned long flags;
> int rc = 0;
>
> - rc = kstrtol(buf, 10, &input);
> - if (rc)
> - return rc;
> - if ((input < 0) || (input > 1))
> - return -EINVAL;
> + spin_lock_irqsave(ap->lock, flags);

Any reason to not use spin_lock_irq() ?

>
> - ap = ata_shost_to_port(sdev->host);
> dev = ata_scsi_find_dev(ap, sdev);
> - if (unlikely(!dev))
> - return -ENODEV;
> -
> - spin_lock_irq(ap->lock);
> + if (unlikely(!dev)) {
> + rc = -ENODEV;
> + goto unlock;
> + }
>
> if (!(dev->flags & ATA_DFLAG_NCQ_PRIO)) {
> rc = -EINVAL;
> goto unlock;
> }
>
> - if (input) {
> + if (enable) {
> if (dev->flags & ATA_DFLAG_CDL_ENABLED) {
> ata_dev_err(dev,
> "CDL must be disabled to enable NCQ priority\n");
> @@ -934,9 +958,27 @@ static ssize_t ata_ncq_prio_enable_store(struct device *device,
> }
>
> unlock:
> - spin_unlock_irq(ap->lock);
> + spin_unlock_irqrestore(ap->lock, flags);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(ata_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 = ata_shost_to_port(sdev->host);
> + long input;
> + int rc = 0;
> +
> + rc = kstrtol(buf, 10, &input);

Please use kstrtobool().

> + if (rc)
> + return rc;
> + if ((input < 0) || (input > 1))
> + return -EINVAL;
>
> - return rc ? rc : len;
> + return ata_ncq_prio_enable(ap, sdev, input) ? : len;
> }
>
> DEVICE_ATTR(ncq_prio_enable, S_IRUGO | S_IWUSR,
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 26d68115afb8..f3ff2bf3ec6b 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -1157,6 +1157,10 @@ extern int ata_scsi_change_queue_depth(struct scsi_device *sdev,
> int queue_depth);
> extern int ata_change_queue_depth(struct ata_port *ap, struct scsi_device *sdev,
> int queue_depth);
> +extern int ata_ncq_prio_supported(struct ata_port *ap, struct scsi_device *sdev);
> +extern int ata_ncq_prio_enabled(struct ata_port *ap, struct scsi_device *sdev);
> +extern int ata_ncq_prio_enable(struct ata_port *ap, struct scsi_device *sdev,
> + bool enable);
> extern struct ata_device *ata_dev_pair(struct ata_device *adev);
> extern int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev);
> extern void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap);

--
Damien Le Moal
Western Digital Research