block: convert to dequeueing model (easy ones)

plat-omap/mailbox, floppy, viocd, mspro_block, i2o_block and
mmc/card/queue are already pretty close to dequeueing model and can be
converted with simple changes.  Convert them.

While at it,

* xen-blkfront: !fs check moved downwards to share dequeue call with
  normal path.

* mspro_block: __blk_end_request(..., blk_rq_cur_byte()) converted to
  __blk_end_request_cur()

* mmc/card/queue: loop of __blk_end_request() converted to
  __blk_end_request_all()

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

7 files changed, 36 insertions, 18 deletions

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 538ba7541d3f..7a1f5c25fd17 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -198,6 +198,8 @@ static void mbox_tx_work(struct work_struct *work)
 
                 spin_lock(q->queue_lock);
                 rq = elv_next_request(q);
+                if (rq)
+                        blkdev_dequeue_request(rq);
                 spin_unlock(q->queue_lock);
 
                 if (!rq)
@@ -208,6 +210,9 @@ static void mbox_tx_work(struct work_struct *work)
                 ret = __mbox_msg_send(mbox, tx_data->msg, tx_data->arg);
                 if (ret) {
                         enable_mbox_irq(mbox, IRQ_TX);
+                        spin_lock(q->queue_lock);
+                        blk_requeue_request(q, rq);
+                        spin_unlock(q->queue_lock);
                         return;
                 }
 
@@ -238,6 +243,8 @@ static void mbox_rx_work(struct work_struct *work)
         while (1) {
                 spin_lock_irqsave(q->queue_lock, flags);
                 rq = elv_next_request(q);
+                if (rq)
+                        blkdev_dequeue_request(rq);
                 spin_unlock_irqrestore(q->queue_lock, flags);
                 if (!rq)
                         break;
@@ -345,6 +352,8 @@ omap_mbox_read(struct device *dev, struct device_attribute *attr, char *buf)
         while (1) {
                 spin_lock_irqsave(q->queue_lock, flags);
                 rq = elv_next_request(q);
+                if (rq)
+                        blkdev_dequeue_request(rq);
                 spin_unlock_irqrestore(q->queue_lock, flags);
 
                 if (!rq)
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 1e27ed9208b4..e2c70d2085ae 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -931,7 +931,7 @@ static inline void unlock_fdc(void)
         del_timer(&fd_timeout);
         cont = NULL;
         clear_bit(0, &fdc_busy);
-        if (elv_next_request(floppy_queue))
+        if (current_req || elv_next_request(floppy_queue))
                 do_fd_request(floppy_queue);
         spin_unlock_irqrestore(&floppy_lock, flags);
         wake_up(&fdc_wait);
@@ -2913,6 +2913,8 @@ static void redo_fd_request(void)
 
                         spin_lock_irq(floppy_queue->queue_lock);
                         req = elv_next_request(floppy_queue);
+                        if (req)
+                                blkdev_dequeue_request(req);
                         spin_unlock_irq(floppy_queue->queue_lock);
                         if (!req) {
                                 do_floppy = NULL;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 91fc56597e9b..66f834571b88 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -301,22 +301,23 @@ static void do_blkif_request(struct request_queue *rq)
 
         while ((req = elv_next_request(rq)) != NULL) {
                 info = req->rq_disk->private_data;
-                if (!blk_fs_request(req)) {
-                        __blk_end_request_cur(req, -EIO);
-                        continue;
-                }
 
                 if (RING_FULL(&info->ring))
                         goto wait;
 
+                blkdev_dequeue_request(req);
+
+                if (!blk_fs_request(req)) {
+                        __blk_end_request_all(req, -EIO);
+                        continue;
+                }
+
                 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
                          "(%u/%u) buffer:%p [%s]\n",
                          req, req->cmd, (unsigned long)blk_rq_pos(req),
                          blk_rq_cur_sectors(req), blk_rq_sectors(req),
                          req->buffer, rq_data_dir(req) ? "write" : "read");
 
-
-                blkdev_dequeue_request(req);
                 if (blkif_queue_request(req)) {
                         blk_requeue_request(rq, req);
 wait:
diff --git a/drivers/cdrom/viocd.c b/drivers/cdrom/viocd.c
index 6e190a93d8df..bbe9f0867347 100644
--- a/drivers/cdrom/viocd.c
+++ b/drivers/cdrom/viocd.c
@@ -298,6 +298,8 @@ static void do_viocd_request(struct request_queue *q)
         struct request *req;
 
         while ((rwreq == 0) && ((req = elv_next_request(q)) != NULL)) {
+                blkdev_dequeue_request(req);
+
                 if (!blk_fs_request(req))
                         __blk_end_request_all(req, -EIO);
                 else if (send_request(req) < 0) {
diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index 93b2c6185656..58f5be8cd69e 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -672,8 +672,7 @@ try_again:
                                                msb->req_sg);
 
                 if (!msb->seg_count) {
-                        chunk = __blk_end_request(msb->block_req, -ENOMEM,
-                                        blk_rq_cur_bytes(msb->block_req));
+                        chunk = __blk_end_request_cur(msb->block_req, -ENOMEM);
                         continue;
                 }
 
@@ -711,6 +710,7 @@ try_again:
                 dev_dbg(&card->dev, "issue end\n");
                 return -EAGAIN;
         }
+        blkdev_dequeue_request(msb->block_req);
 
         dev_dbg(&card->dev, "trying again\n");
         chunk = 1;
@@ -825,8 +825,10 @@ static void mspro_block_submit_req(struct request_queue *q)
                 return;
 
         if (msb->eject) {
-                while ((req = elv_next_request(q)) != NULL)
+                while ((req = elv_next_request(q)) != NULL) {
+                        blkdev_dequeue_request(req);
                         __blk_end_request_all(req, -ENODEV);
+                }
 
                 return;
         }
diff --git a/drivers/message/i2o/i2o_block.c b/drivers/message/i2o/i2o_block.c
index e153f5d5237d..8b5cbfc3ba97 100644
--- a/drivers/message/i2o/i2o_block.c
+++ b/drivers/message/i2o/i2o_block.c
@@ -916,8 +916,10 @@ static void i2o_block_request_fn(struct request_queue *q)
                                 blk_stop_queue(q);
                                 break;
                         }
-                } else
-                        __blk_end_request_cur(req, -EIO);
+                } else {
+                        blkdev_dequeue_request(req);
+                        __blk_end_request_all(req, -EIO);
+                }
         }
 };
 
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 7a72e75d5c67..4b70f1e28347 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -54,8 +54,11 @@ static int mmc_queue_thread(void *d)
 
                 spin_lock_irq(q->queue_lock);
                 set_current_state(TASK_INTERRUPTIBLE);
-                if (!blk_queue_plugged(q))
+                if (!blk_queue_plugged(q)) {
                         req = elv_next_request(q);
+                        if (req)
+                                blkdev_dequeue_request(req);
+                }
                 mq->req = req;
                 spin_unlock_irq(q->queue_lock);
 
@@ -88,15 +91,12 @@ static void mmc_request(struct request_queue *q)
 {
         struct mmc_queue *mq = q->queuedata;
         struct request *req;
-        int ret;
 
         if (!mq) {
                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
                 while ((req = elv_next_request(q)) != NULL) {
-                        do {
-                                ret = __blk_end_request(req, -EIO,
-                                                        blk_rq_cur_bytes(req));
-                        } while (ret);
+                        blkdev_dequeue_request(req);
+                        __blk_end_request_all(req, -EIO);
                 }
                 return;
         }