scsi: don't add scsi_device if its already visible

If LLD has added scsi device (by calling scsi_add_device) before scheduling
async scsi_scan_host then scsi_finish_async_scan() will end up calling
scsi_sysfs_add_sdev for scsi device which was already added by LLD.
This patch fixes this issue by skipping the call to scsi_sysfs_add_sdev()
if it's already visible to rest of the kernel.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/scsi_scan.c

@@ -1756,6 +1756,9 @@ static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
 		/* target removed before the device could be added */
 		if (sdev->sdev_state == SDEV_DEL)
 			continue;
+		/* If device is already visible, skip adding it to sysfs */
+		if (sdev->is_visible)
+			continue;
 		if (!scsi_host_scan_allowed(shost) ||
 		    scsi_sysfs_add_sdev(sdev) != 0)
 			__scsi_remove_device(sdev);