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>

3 files changed, 28 insertions, 18 deletions

diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index 2d5dc0af55e4..425f81586a31 100644
--- a/drivers/block/paride/pcd.c
+++ b/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);
diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index 9ec5d4ac0b64..d2ca3f552061 100644
--- a/drivers/block/paride/pd.c
+++ b/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();
 }
diff --git a/drivers/block/paride/pf.c b/drivers/block/paride/pf.c
index e88c889aa7f2..d6f7bd84ed39 100644
--- a/drivers/block/paride/pf.c
+++ b/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;