xd: dequeue in-flight request
Tejun Heo [Fri, 8 May 2009 02:54:10 +0000 (11:54 +0900)]
xd processes requests one-by-one synchronously and can be easily
converted to dequeueing model.  Convert it.

While at it, use rq_cur_bytes instead of rq_bytes when checking for
sector overflow.  This is for for consistency and better behavior for
merged requests.

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/xd.c

index 4ef8801..d4c4352 100644 (file)
@@ -305,26 +305,31 @@ static void do_xd_request (struct request_queue * q)
        if (xdc_busy)
                return;
 
-       while ((req = elv_next_request(q)) != NULL) {
+       req = elv_next_request(q);
+       if (req)
+               blkdev_dequeue_request(req);
+
+       while (req) {
                unsigned block = blk_rq_pos(req);
-               unsigned count = blk_rq_sectors(req);
+               unsigned count = blk_rq_cur_sectors(req);
                XD_INFO *disk = req->rq_disk->private_data;
-               int res = 0;
+               int res = -EIO;
                int retry;
 
-               if (!blk_fs_request(req)) {
-                       __blk_end_request_cur(req, -EIO);
-                       continue;
-               }
-               if (block + count > get_capacity(req->rq_disk)) {
-                       __blk_end_request_cur(req, -EIO);
-                       continue;
-               }
+               if (!blk_fs_request(req))
+                       goto done;
+               if (block + count > get_capacity(req->rq_disk))
+                       goto done;
                for (retry = 0; (retry < XD_RETRIES) && !res; retry++)
                        res = xd_readwrite(rq_data_dir(req), disk, req->buffer,
                                           block, count);
+       done:
                /* wrap up, 0 = success, -errno = fail */
-               __blk_end_request_cur(req, res);
+               if (!__blk_end_request_cur(req, res)) {
+                       req = elv_next_request(q);
+                       if (req)
+                               blkdev_dequeue_request(req);
+               }
        }
 }