xd: dequeue in-flight request

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>

1 files changed, 17 insertions, 12 deletions

diff --git a/drivers/block/xd.c b/drivers/block/xd.c
index 4ef88018bcde..d4c4352354b5 100644
--- a/drivers/block/xd.c
+++ b/drivers/block/xd.c
@@ -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);
+                }
         }
 }