paride: dequeue in-flight request

pd/pf/pcd have track in-flight request by pd/pf/pcd_req.  They can be
converted to dequeueing model by updating fetching and completion
paths.  Convert them.

Note that removal of elv_next_request() call from pf_next_buf()
doesn't make any functional difference.  The path is traveled only
during partial completion of a request and elv_next_request() call
must return the same request anyway.

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/paride/pcd.c

@@ -719,9 +719,12 @@ static void do_pcd_request(struct request_queue * q)
 	if (pcd_busy)
 		return;
 	while (1) {
-		pcd_req = elv_next_request(q);
-		if (!pcd_req)
-			return;
+		if (!pcd_req) {
+			pcd_req = elv_next_request(q);
+			if (!pcd_req)
+				return;
+			blkdev_dequeue_request(pcd_req);
+		}
 
 		if (rq_data_dir(pcd_req) == READ) {
 			struct pcd_unit *cd = pcd_req->rq_disk->private_data;
@@ -734,8 +737,10 @@ static void do_pcd_request(struct request_queue * q)
 			pcd_busy = 1;
 			ps_set_intr(do_pcd_read, NULL, 0, nice);
 			return;
-		} else
-			__blk_end_request_cur(pcd_req, -EIO);
+		} else {
+			__blk_end_request_all(pcd_req, -EIO);
+			pcd_req = NULL;
+		}
 	}
 }
 
@@ -744,7 +749,8 @@ static inline void next_request(int err)
 	unsigned long saved_flags;
 
 	spin_lock_irqsave(&pcd_lock, saved_flags);
-	__blk_end_request_cur(pcd_req, err);
+	if (!__blk_end_request_cur(pcd_req, err))
+		pcd_req = NULL;
 	pcd_busy = 0;
 	do_pcd_request(pcd_queue);
 	spin_unlock_irqrestore(&pcd_lock, saved_flags);

drivers/block/paride/pd.c

@@ -410,11 +410,14 @@ static void run_fsm(void)
 				pd_claimed = 0;
 				phase = NULL;
 				spin_lock_irqsave(&pd_lock, saved_flags);
-				__blk_end_request_cur(pd_req,
-						      res == Ok ? 0 : -EIO);
-				pd_req = elv_next_request(pd_queue);
-				if (!pd_req)
-					stop = 1;
+				if (!__blk_end_request_cur(pd_req,
+						res == Ok ? 0 : -EIO)) {
+					pd_req = elv_next_request(pd_queue);
+					if (!pd_req)
+						stop = 1;
+					else
+						blkdev_dequeue_request(pd_req);
+				}
 				spin_unlock_irqrestore(&pd_lock, saved_flags);
 				if (stop)
 					return;
@@ -706,6 +709,7 @@ static void do_pd_request(struct request_queue * q)
 	pd_req = elv_next_request(q);
 	if (!pd_req)
 		return;
+	blkdev_dequeue_request(pd_req);
 
 	schedule_fsm();
 }

drivers/block/paride/pf.c

@@ -752,10 +752,8 @@ static struct request_queue *pf_queue;
 
 static void pf_end_request(int err)
 {
-	if (pf_req) {
-		__blk_end_request_cur(pf_req, err);
+	if (pf_req && !__blk_end_request_cur(pf_req, err))
 		pf_req = NULL;
-	}
 }
 
 static void do_pf_request(struct request_queue * q)
@@ -763,9 +761,12 @@ static void do_pf_request(struct request_queue * q)
 	if (pf_busy)
 		return;
 repeat:
-	pf_req = elv_next_request(q);
-	if (!pf_req)
-		return;
+	if (!pf_req) {
+		pf_req = elv_next_request(q);
+		if (!pf_req)
+			return;
+		blkdev_dequeue_request(pf_req);
+	}
 
 	pf_current = pf_req->rq_disk->private_data;
 	pf_block = blk_rq_pos(pf_req);
@@ -806,7 +807,6 @@ static int pf_next_buf(void)
 	if (!pf_count) {
 		spin_lock_irqsave(&pf_spin_lock, saved_flags);
 		pf_end_request(0);
-		pf_req = elv_next_request(pf_queue);
 		spin_unlock_irqrestore(&pf_spin_lock, saved_flags);
 		if (!pf_req)
 			return 1;