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

[Damien Le Moal <dlemoal@kernel.org>]

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