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

Igor Pylypiv
2024-03-01T22:58:21Z

On Fri, Mar 01, 2024 at 04:16:46AM -0800, Damien Le Moal wrote:

Thank you for the review Damien!

> 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() ?

In the future someone might call these helper functions when interrupts
are disabled. spin_unlock_irq() might re-enable interrupts prematurely.
spin_unlock_irqrestore() will restore the same interrupts state that was
before the call to spin_lock_irqsave().

>
> >
> > - 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
>