On Sun, Jan 8, 2012 at 5:57 PM, Jack Wang <jack_wang@xxxxxxxxx> wrote:
>> +int isci_ata_check_ready(struct domain_device *dev)
>> +{
>> + struct isci_port *iport = dev->port->lldd_port;
>> + struct isci_host *ihost = dev_to_ihost(dev);
>> + struct isci_remote_device *idev;
>> + unsigned long flags;
>> + int rc = 0;
>> +
>> + spin_lock_irqsave(&ihost->scic_lock, flags);
>> + idev = isci_lookup_device(dev);
>> + spin_unlock_irqrestore(&ihost->scic_lock, flags);
>> +
>> + if (!idev)
>> + goto out;
>> +
>> + if (test_bit(IPORT_RESET_PENDING, &iport->state))
>> + goto out;
>> +
>> + /* snapshot active phy mask */
>> + spin_lock_irqsave(&ihost->scic_lock, flags);
>> + rc = !!iport->active_phy_mask;
> [Jack Wang]
> Hi Dan,
>
> Could you explain why here you not directly use "
> rc = !!iport->active_phy_mask;
You are right, it can look at the field outside the lock... and since
we have already taken the lock to get a device reference we know we
have flushed any recent port events.
--
Dan
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