block: implement and use [__]blk_end_request_all()

There are many [__]blk_end_request() call sites which call it with
full request length and expect full completion.  Many of them ensure
that the request actually completes by doing BUG_ON() the return
value, which is awkward and error-prone.

This patch adds [__]blk_end_request_all() which takes @rq and @error
and fully completes the request.  BUG_ON() is added to to ensure that
this actually happens.

Most conversions are simple but there are a few noteworthy ones.

* cdrom/viocd: viocd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/block/dasd: dasd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/char/tape_block: tapeblock_end_request() replaced with direct
  calls to blk_end_request_all().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>

15 files changed, 58 insertions, 73 deletions

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 0abfbaa5987..cf81bad8aec 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -192,8 +192,7 @@ static void mbox_tx_work(struct work_struct *work)
                 }
 
                 spin_lock(q->queue_lock);
-                if (__blk_end_request(rq, 0, 0))
-                        BUG();
+                __blk_end_request_all(rq, 0);
                 spin_unlock(q->queue_lock);
         }
 }
@@ -224,10 +223,7 @@ static void mbox_rx_work(struct work_struct *work)
                         break;
 
                 msg = (mbox_msg_t) rq->data;
-
-                if (blk_end_request(rq, 0, 0))
-                        BUG();
-
+                blk_end_request_all(rq, 0);
                 mbox->rxq->callback((void *)msg);
         }
 }
@@ -337,8 +333,7 @@ omap_mbox_read(struct device *dev, struct device_attribute *attr, char *buf)
 
                 *p = (mbox_msg_t) rq->data;
 
-                if (blk_end_request(rq, 0, 0))
-                        BUG();
+                blk_end_request_all(rq, 0);
 
                 if (unlikely(mbox_seq_test(mbox, *p))) {
                         pr_info("mbox: Illegal seq bit!(%08x) ignored\n", *p);
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 20b4111fa05..c8d087655ef 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -106,10 +106,7 @@ bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
          */
         q->ordseq = 0;
         rq = q->orig_bar_rq;
-
-        if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
-                BUG();
-
+        __blk_end_request_all(rq, q->orderr);
         return true;
 }
 
@@ -252,9 +249,7 @@ bool blk_do_ordered(struct request_queue *q, struct request **rqp)
                          * with prejudice.
                          */
                         elv_dequeue_request(q, rq);
-                        if (__blk_end_request(rq, -EOPNOTSUPP,
-                                              blk_rq_bytes(rq)))
-                                BUG();
+                        __blk_end_request_all(rq, -EOPNOTSUPP);
                         *rqp = NULL;
                         return false;
                 }
diff --git a/block/blk-core.c b/block/blk-core.c
index b84250d3019..0520cc70458 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1780,7 +1780,7 @@ struct request *elv_next_request(struct request_queue *q)
                         break;
                 } else if (ret == BLKPREP_KILL) {
                         rq->cmd_flags |= REQ_QUIET;
-                        __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
+                        __blk_end_request_all(rq, -EIO);
                 } else {
                         printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
                         break;
diff --git a/block/elevator.c b/block/elevator.c
index b03b8752e18..1af5d9f04af 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -810,7 +810,7 @@ void elv_abort_queue(struct request_queue *q)
                 rq = list_entry_rq(q->queue_head.next);
                 rq->cmd_flags |= REQ_QUIET;
                 trace_block_rq_abort(q, rq);
-                __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
+                __blk_end_request_all(rq, -EIO);
         }
 }
 EXPORT_SYMBOL(elv_abort_queue);
diff --git a/drivers/block/cpqarray.c b/drivers/block/cpqarray.c
index ca268ca1115..488a8f4a60a 100644
--- a/drivers/block/cpqarray.c
+++ b/drivers/block/cpqarray.c
@@ -1024,8 +1024,7 @@ static inline void complete_command(cmdlist_t *cmd, int timeout)
                                 cmd->req.sg[i].size, ddir);
 
         DBGPX(printk("Done with %p\n", rq););
-        if (__blk_end_request(rq, error, blk_rq_bytes(rq)))
-                BUG();
+        __blk_end_request_all(rq, error);
 }
 
 /*
diff --git a/drivers/block/sx8.c b/drivers/block/sx8.c
index ff0448e4bf0..60e85bb6f79 100644
--- a/drivers/block/sx8.c
+++ b/drivers/block/sx8.c
@@ -749,8 +749,7 @@ static inline void carm_end_request_queued(struct carm_host *host,
         struct request *req = crq->rq;
         int rc;
 
-        rc = __blk_end_request(req, error, blk_rq_bytes(req));
-        assert(rc == 0);
+        __blk_end_request_all(req, error);
 
         rc = carm_put_request(host, crq);
         assert(rc == 0);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 5d34764c8a8..50745e64414 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -62,7 +62,7 @@ static void blk_done(struct virtqueue *vq)
                         break;
                 }
 
-                __blk_end_request(vbr->req, error, blk_rq_bytes(vbr->req));
+                __blk_end_request_all(vbr->req, error);
                 list_del(&vbr->list);
                 mempool_free(vbr, vblk->pool);
         }
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8f905089b72..cd6cfe3b51e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -551,7 +551,6 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 
         for (i = info->ring.rsp_cons; i != rp; i++) {
                 unsigned long id;
-                int ret;
 
                 bret = RING_GET_RESPONSE(&info->ring, i);
                 id   = bret->id;
@@ -578,8 +577,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
                                 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
                                         "request: %x\n", bret->status);
 
-                        ret = __blk_end_request(req, error, blk_rq_bytes(req));
-                        BUG_ON(ret);
+                        __blk_end_request_all(req, error);
                         break;
                 default:
                         BUG();
diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index 2eecb779437..fee9a9e83fc 100644
--- a/drivers/cdrom/gdrom.c
+++ b/drivers/cdrom/gdrom.c
@@ -632,7 +632,7 @@ static void gdrom_readdisk_dma(struct work_struct *work)
                 * before handling ending the request */
                 spin_lock(&gdrom_lock);
                 list_del_init(&req->queuelist);
-                __blk_end_request(req, err, blk_rq_bytes(req));
+                __blk_end_request_all(req, err);
         }
         spin_unlock(&gdrom_lock);
         kfree(read_command);
diff --git a/drivers/cdrom/viocd.c b/drivers/cdrom/viocd.c
index 13929356135..cc3efa096e1 100644
--- a/drivers/cdrom/viocd.c
+++ b/drivers/cdrom/viocd.c
@@ -291,23 +291,6 @@ static int send_request(struct request *req)
         return 0;
 }
 
-static void viocd_end_request(struct request *req, int error)
-{
-        int nsectors = req->hard_nr_sectors;
-
-        /*
-         * Make sure it's fully ended, and ensure that we process
-         * at least one sector.
-         */
-        if (blk_pc_request(req))
-                nsectors = (req->data_len + 511) >> 9;
-        if (!nsectors)
-                nsectors = 1;
-
-        if (__blk_end_request(req, error, nsectors << 9))
-                BUG();
-}
-
 static int rwreq;
 
 static void do_viocd_request(struct request_queue *q)
@@ -316,11 +299,11 @@ static void do_viocd_request(struct request_queue *q)
 
         while ((rwreq == 0) && ((req = elv_next_request(q)) != NULL)) {
                 if (!blk_fs_request(req))
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 else if (send_request(req) < 0) {
                         printk(VIOCD_KERN_WARNING
                                         "unable to send message to OS/400!");
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 } else
                         rwreq++;
         }
@@ -531,9 +514,9 @@ return_complete:
                                         "with rc %d:0x%04X: %s\n",
                                         req, event->xRc,
                                         bevent->sub_result, err->msg);
-                        viocd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                 } else
-                        viocd_end_request(req, 0);
+                        __blk_end_request_all(req, 0);
 
                 /* restart handling of incoming requests */
                 spin_unlock_irqrestore(&viocd_reqlock, flags);
diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index de143deb06f..a41634699f8 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -826,7 +826,7 @@ static void mspro_block_submit_req(struct request_queue *q)
 
         if (msb->eject) {
                 while ((req = elv_next_request(q)) != NULL)
-                        __blk_end_request(req, -ENODEV, blk_rq_bytes(req));
+                        __blk_end_request_all(req, -ENODEV);
 
                 return;
         }
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index d1815272c43..fabec95686b 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1614,15 +1614,6 @@ void dasd_block_clear_timer(struct dasd_block *block)
 }
 
 /*
- * posts the buffer_cache about a finalized request
- */
-static inline void dasd_end_request(struct request *req, int error)
-{
-        if (__blk_end_request(req, error, blk_rq_bytes(req)))
-                BUG();
-}
-
-/*
  * Process finished error recovery ccw.
  */
 static inline void __dasd_block_process_erp(struct dasd_block *block,
@@ -1676,7 +1667,7 @@ static void __dasd_process_request_queue(struct dasd_block *block)
                                       "Rejecting write request %p",
                                       req);
                         blkdev_dequeue_request(req);
-                        dasd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                         continue;
                 }
                 cqr = basedev->discipline->build_cp(basedev, block, req);
@@ -1705,7 +1696,7 @@ static void __dasd_process_request_queue(struct dasd_block *block)
                                       "on request %p",
                                       PTR_ERR(cqr), req);
                         blkdev_dequeue_request(req);
-                        dasd_end_request(req, -EIO);
+                        __blk_end_request_all(req, -EIO);
                         continue;
                 }
                 /*
@@ -1731,7 +1722,7 @@ static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
         status = cqr->block->base->discipline->free_cp(cqr, req);
         if (status <= 0)
                 error = status ? status : -EIO;
-        dasd_end_request(req, error);
+        __blk_end_request_all(req, error);
 }
 
 /*
@@ -2040,7 +2031,7 @@ static void dasd_flush_request_queue(struct dasd_block *block)
         spin_lock_irq(&block->request_queue_lock);
         while ((req = elv_next_request(block->request_queue))) {
                 blkdev_dequeue_request(req);
-                dasd_end_request(req, -EIO);
+                __blk_end_request_all(req, -EIO);
         }
         spin_unlock_irq(&block->request_queue_lock);
 }
diff --git a/drivers/s390/char/tape_block.c b/drivers/s390/char/tape_block.c
index f32e89e7c4f..86596d3813b 100644
--- a/drivers/s390/char/tape_block.c
+++ b/drivers/s390/char/tape_block.c
@@ -74,13 +74,6 @@ tapeblock_trigger_requeue(struct tape_device *device)
  * Post finished request.
  */
 static void
-tapeblock_end_request(struct request *req, int error)
-{
-        if (blk_end_request(req, error, blk_rq_bytes(req)))
-                BUG();
-}
-
-static void
 __tapeblock_end_request(struct tape_request *ccw_req, void *data)
 {
         struct tape_device *device;
@@ -90,7 +83,7 @@ __tapeblock_end_request(struct tape_request *ccw_req, void *data)
 
         device = ccw_req->device;
         req = (struct request *) data;
-        tapeblock_end_request(req, (ccw_req->rc == 0) ? 0 : -EIO);
+        blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO);
         if (ccw_req->rc == 0)
                 /* Update position. */
                 device->blk_data.block_position =
@@ -118,7 +111,7 @@ tapeblock_start_request(struct tape_device *device, struct request *req)
         ccw_req = device->discipline->bread(device, req);
         if (IS_ERR(ccw_req)) {
                 DBF_EVENT(1, "TBLOCK: bread failed\n");
-                tapeblock_end_request(req, -EIO);
+                blk_end_request_all(req, -EIO);
                 return PTR_ERR(ccw_req);
         }
         ccw_req->callback = __tapeblock_end_request;
@@ -131,7 +124,7 @@ tapeblock_start_request(struct tape_device *device, struct request *req)
                  * Start/enqueueing failed. No retries in
                  * this case.
                  */
-                tapeblock_end_request(req, -EIO);
+                blk_end_request_all(req, -EIO);
                 device->discipline->free_bread(ccw_req);
         }
 
@@ -177,7 +170,7 @@ tapeblock_requeue(struct work_struct *work) {
                         DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
                         blkdev_dequeue_request(req);
                         spin_unlock_irq(&device->blk_data.request_queue_lock);
-                        tapeblock_end_request(req, -EIO);
+                        blk_end_request_all(req, -EIO);
                         spin_lock_irq(&device->blk_data.request_queue_lock);
                         continue;
                 }
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d1cb64ad1a3..756ac7c93de 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -922,7 +922,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                         if (driver_byte(result) & DRIVER_SENSE)
                                 scsi_print_sense("", cmd);
                 }
-                blk_end_request(req, -EIO, blk_rq_bytes(req));
+                blk_end_request_all(req, -EIO);
                 scsi_next_command(cmd);
                 break;
         case ACTION_REPREP:
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 501f6845cc7..e33c8356b3d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -883,6 +883,22 @@ static inline bool blk_end_request(struct request *rq, int error,
 }
 
 /**
+ * blk_end_request_all - Helper function for drives to finish the request.
+ * @rq: the request to finish
+ * @err: %0 for success, < %0 for error
+ *
+ * Description:
+ *     Completely finish @rq.
+ */
+static inline void blk_end_request_all(struct request *rq, int error)
+{
+        bool pending;
+
+        pending = blk_end_request(rq, error, blk_rq_bytes(rq));
+        BUG_ON(pending);
+}
+
+/**
  * __blk_end_request - Helper function for drivers to complete the request.
  * @rq:       the request being processed
  * @error:    %0 for success, < %0 for error
@@ -902,6 +918,22 @@ static inline bool __blk_end_request(struct request *rq, int error,
 }
 
 /**
+ * __blk_end_request_all - Helper function for drives to finish the request.
+ * @rq: the request to finish
+ * @err: %0 for success, < %0 for error
+ *
+ * Description:
+ *     Completely finish @rq.  Must be called with queue lock held.
+ */
+static inline void __blk_end_request_all(struct request *rq, int error)
+{
+        bool pending;
+
+        pending = __blk_end_request(rq, error, blk_rq_bytes(rq));
+        BUG_ON(pending);
+}
+
+/**
  * end_request - end I/O on the current segment of the request
  * @rq:         the request being processed
  * @uptodate:   error value or %0/%1 uptodate flag