swim: clean up request completion paths

swim curiously tries to update request parameters before calling
__blk_end_request() when __blk_end_request() will do it anyway and
unnecessarily checks whether current_nr_sectors is zero right after
fetching.

Drop unnecessary stuff and use standard block layer mechanisms.

[ Impact: cleanup ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/swim.c

@@ -535,10 +535,6 @@ static void redo_fd_request(struct request_queue *q)
 			__blk_end_request_cur(req, -EIO);
 			continue;
 		}
-		if (req->current_nr_sectors == 0) {
-			__blk_end_request_cur(req, 0);
-			continue;
-		}
 		if (!fs->disk_in) {
 			__blk_end_request_cur(req, -EIO);
 			continue;
@@ -561,9 +557,6 @@ static void redo_fd_request(struct request_queue *q)
 				__blk_end_request_cur(req, -EIO);
 				continue;
 			}
-			req->nr_sectors -= req->current_nr_sectors;
-			req->sector += req->current_nr_sectors;
-			req->buffer += req->current_nr_sectors * 512;
 			__blk_end_request_cur(req, 0);
 			break;
 		}