ata: libata-scsi: Improve ata_scsi_handle_link_detach()

A struct ata_device flags should always be set and cleared with the
device port locked. Testing for a flag should thus also be done while
holding the device port lock. In accordance to this principle, modify
ata_scsi_handle_link_detach() to test and clear the ATA_DFLAG_DETACHED
flag while holding the device port lock.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

drivers/ata/libata-scsi.c

@@ -4605,10 +4605,12 @@ static void ata_scsi_handle_link_detach(struct ata_link *link)
 	ata_for_each_dev(dev, link, ALL) {
 		unsigned long flags;
 
-		if (!(dev->flags & ATA_DFLAG_DETACHED))
+		spin_lock_irqsave(ap->lock, flags);
+		if (!(dev->flags & ATA_DFLAG_DETACHED)) {
+			spin_unlock_irqrestore(ap->lock, flags);
 			continue;
+		}
 
-		spin_lock_irqsave(ap->lock, flags);
 		dev->flags &= ~ATA_DFLAG_DETACHED;
 		spin_unlock_irqrestore(ap->lock, flags);