swim: dequeue in-flight request

swim processes requests one-by-one synchronously and can easily be
converted to dequeuing model.  Convert it.

[ Impact: dequeue in-flight request ]
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

@@ -514,7 +514,7 @@ static int floppy_read_sectors(struct floppy_state *fs,
 			ret = swim_read_sector(fs, side, track, sector,
 						buffer);
 			if (try-- == 0)
-				return -1;
+				return -EIO;
 		} while (ret != 512);
 
 		buffer += ret;
@@ -528,38 +528,37 @@ static void redo_fd_request(struct request_queue *q)
 	struct request *req;
 	struct floppy_state *fs;
 
-	while ((req = elv_next_request(q))) {
+	req = elv_next_request(q);
+	if (req)
+		blkdev_dequeue_request(req);
+
+	while (req) {
+		int err = -EIO;
 
 		fs = req->rq_disk->private_data;
-		if (blk_rq_pos(req) >= fs->total_secs) {
-			__blk_end_request_cur(req, -EIO);
-			continue;
-		}
-		if (!fs->disk_in) {
-			__blk_end_request_cur(req, -EIO);
-			continue;
-		}
-		if (rq_data_dir(req) == WRITE) {
-			if (fs->write_protected) {
-				__blk_end_request_cur(req, -EIO);
-				continue;
-			}
-		}
+		if (blk_rq_pos(req) >= fs->total_secs)
+			goto done;
+		if (!fs->disk_in)
+			goto done;
+		if (rq_data_dir(req) == WRITE && fs->write_protected)
+			goto done;
+
 		switch (rq_data_dir(req)) {
 		case WRITE:
 			/* NOT IMPLEMENTED */
-			__blk_end_request_cur(req, -EIO);
 			break;
 		case READ:
-			if (floppy_read_sectors(fs, blk_rq_pos(req),
+			err = floppy_read_sectors(fs, blk_rq_pos(req),
 						  blk_rq_cur_sectors(req),
-						req->buffer)) {
-				__blk_end_request_cur(req, -EIO);
-				continue;
-			}
-			__blk_end_request_cur(req, 0);
+						  req->buffer);
 			break;
 		}
+	done:
+		if (!__blk_end_request_cur(req, err)) {
+			req = elv_next_request(q);
+			if (req)
+				blkdev_dequeue_request(req);
+		}
 	}
 }