z2ram: dequeue in-flight request

z2ram processes requests one-by-one synchronously and can be easily
converted to dequeueing model.  Convert it.

[ 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, 15 insertions, 4 deletions

diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 6a1383834ecf..c909c1a3f650 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk;
 static void do_z2_request(struct request_queue *q)
 {
         struct request *req;
-        while ((req = elv_next_request(q)) != NULL) {
+
+        req = elv_next_request(q);
+        if (req)
+                blkdev_dequeue_request(req);
+
+        while (req) {
                 unsigned long start = blk_rq_pos(req) << 9;
                 unsigned long len  = blk_rq_cur_bytes(req);
+                int err = 0;
 
                 if (start + len > z2ram_size) {
                         printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu, count=%u\n",
                                 blk_rq_pos(req), blk_rq_cur_sectors(req));
-                        __blk_end_request_cur(req, -EIO);
-                        continue;
+                        err = -EIO;
+                        goto done;
                 }
                 while (len) {
                         unsigned long addr = start & Z2RAM_CHUNKMASK;
@@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q)
                         start += size;
                         len -= size;
                 }
-                __blk_end_request_cur(req, 0);
+        done:
+                if (!__blk_end_request_cur(req, err)) {
+                        req = elv_next_request(q);
+                        if (req)
+                                blkdev_dequeue_request(req);
+                }
         }
 }