Elias Oltmanns <eo@xxxxxxxxxxxxxx> wrote:
> What about the following patch?
>
> From: Elias Oltmanns <eo@xxxxxxxxxxxxxx>
> Subject: [PATCH] libata: Implement disk shock protection support
>
> On user request (through sysfs), the IDLE IMMEDIATE command with UNLOAD
> FEATURE as specified in ATA-7 is issued to the device and processing of
> the request queue is stopped thereafter until the specified timeout
> expires or user space asks to resume normal operation. This is supposed
> to prevent the heads of a hard drive from accidentally crashing onto the
> platter when a heavy shock is anticipated (like a falling laptop
> expected to hit the floor). In fact, the whole port stops processing
> commands until the timeout has expired in order to avoid any resets due
> to failed commands on another device.
>
> Signed-off-by: Elias Oltmanns <eo@xxxxxxxxxxxxxx>
> ---
Apart from addressing the issue with timeouts exceeding the limit of
30000 msec discussed lately, I have also simplified the crucial
if-clause in ata_scsi_park_show(). Both changes are given below.
Assuming that you don't have any objections, I'll just go ahead and
submit the updated patch series shortly.
Regards,
Elias
> +static ssize_t ata_scsi_park_show(struct device *device,
> + struct device_attribute *attr, char *buf)
> +{
> + struct scsi_device *sdev = to_scsi_device(device);
> + struct ata_port *ap;
> + struct ata_link *link;
> + struct ata_device *dev;
> + unsigned long flags;
> + unsigned int uninitialized_var(msecs);
> + int rc = 0;
> +
> + ap = ata_shost_to_port(sdev->host);
> +
> + spin_lock_irqsave(ap->lock, flags);
> + dev = ata_scsi_find_dev(ap, sdev);
> + if (!dev) {
> + rc = -ENODEV;
> + goto unlock;
> + }
> + if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
> + rc = -EOPNOTSUPP;
> + goto unlock;
> + }
> +
> + link = dev->link;
> + if (((ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
> + (link->eh_context.i.dev_action[dev->devno] & ATA_EH_PARK ||
> + link->eh_info.dev_action[dev->devno] & ATA_EH_PARK)) ||
> + (ap->pflags & ATA_PFLAG_EH_PENDING &&
> + link->eh_info.dev_action[dev->devno])) &&
> + time_after(dev->unpark_deadline, jiffies))
Changed to:
if (ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
link->eh_context.unloaded_mask & (1 << dev->devno) &&
time_after(dev->unpark_deadline, jiffies))
> + msecs = jiffies_to_msecs(dev->unpark_deadline - jiffies);
> + else
> + msecs = 0;
> +
> +unlock:
> + spin_unlock_irq(ap->lock);
> +
> + return rc ? rc : snprintf(buf, 20, "%u\n", msecs);
> +}
> +
> +static ssize_t ata_scsi_park_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;
> + struct ata_device *dev;
> + long int input;
> + unsigned long flags;
> + int rc;
> +
> + rc = strict_strtol(buf, 10, &input);
> + if (rc || input < -2 || input > ATA_TMOUT_MAX_PARK)
> + return -EINVAL;
Changed to:
if (rc || input < -2)
return -EINVAL;
if (input > ATA_TMOUT_MAX_PARK) {
rc = -EOVERFLOW;
input = ATA_TMOUT_MAX_PARK;
}
> +
> + ap = ata_shost_to_port(sdev->host);
> +
> + spin_lock_irqsave(ap->lock, flags);
> + dev = ata_scsi_find_dev(ap, sdev);
> + if (unlikely(!dev)) {
> + rc = -ENODEV;
> + goto unlock;
> + }
> + if (dev->class != ATA_DEV_ATA) {
> + rc = -EOPNOTSUPP;
> + goto unlock;
> + }
> +
> + if (input >= 0) {
> + if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
> + rc = -EOPNOTSUPP;
> + goto unlock;
> + }
> +
> + dev->unpark_deadline = ata_deadline(jiffies, input);
> + dev->link->eh_info.dev_action[dev->devno] |= ATA_EH_PARK;
> + ata_port_schedule_eh(ap);
> + wake_up_all(&ata_scsi_park_wq);
> + } else {
> + switch (input) {
> + case -1:
> + dev->flags &= ~ATA_DFLAG_NO_UNLOAD;
> + break;
> + case -2:
> + dev->flags |= ATA_DFLAG_NO_UNLOAD;
> + break;
> + }
> + }
> +unlock:
> + spin_unlock_irqrestore(ap->lock, flags);
> +
> + return rc ? rc : len;
> +}
> +DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
> + ata_scsi_park_show, ata_scsi_park_store);
> +EXPORT_SYMBOL_GPL(dev_attr_unload_heads);
> +
> static void ata_scsi_set_sense(struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq)
> {
> cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
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