ata: libata-scsi: Fix ata_scsi_dev_rescan() error path

Commit 0c76106 ("scsi: sd: Fix TCG OPAL unlock on system resume")
incorrectly handles failures of scsi_resume_device() in
ata_scsi_dev_rescan(), leading to a double call to
spin_unlock_irqrestore() to unlock a device port. Fix this by redefining
the goto labels used in case of errors and only unlock the port
scsi_scan_mutex when scsi_resume_device() fails.

Bug found with the Smatch static checker warning:

	drivers/ata/libata-scsi.c:4774 ata_scsi_dev_rescan()
	error: double unlocked 'ap->lock' (orig line 4757)

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 0c76106 ("scsi: sd: Fix TCG OPAL unlock on system resume")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

Author: damien-lemoal

drivers/ata/libata-scsi.c

@@ -4745,7 +4745,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 			 * bail out.
 			 */
 			if (ap->pflags & ATA_PFLAG_SUSPENDED)
-				goto unlock;
+				goto unlock_ap;
 
 			if (!sdev)
 				continue;
@@ -4758,20 +4758,21 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 			if (do_resume) {
 				ret = scsi_resume_device(sdev);
 				if (ret == -EWOULDBLOCK)
-					goto unlock;
+					goto unlock_scan;
 				dev->flags &= ~ATA_DFLAG_RESUMING;
 			}
 			ret = scsi_rescan_device(sdev);
 			scsi_device_put(sdev);
 			spin_lock_irqsave(ap->lock, flags);
 
 			if (ret)
-				goto unlock;
+				goto unlock_ap;
 		}
 	}
 
-unlock:
+unlock_ap:
 	spin_unlock_irqrestore(ap->lock, flags);
+unlock_scan:
 	mutex_unlock(&ap->scsi_scan_mutex);
 
 	/* Reschedule with a delay if scsi_rescan_device() returned an error */