Merge branch 'barrier' into for-linus

23 files changed, 240 insertions, 456 deletions

diff --git a/block/elevator.c b/block/elevator.c
index b9c518afe1f8..952aee04a68a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -712,6 +712,14 @@ struct request *elv_next_request(struct request_queue *q)
         int ret;
 
         while ((rq = __elv_next_request(q)) != NULL) {
+                /*
+                 * Kill the empty barrier place holder, the driver must
+                 * not ever see it.
+                 */
+                if (blk_empty_barrier(rq)) {
+                        end_queued_request(rq, 1);
+                        continue;
+                }
                 if (!(rq->cmd_flags & REQ_STARTED)) {
                         /*
                          * This is the first time the device driver
@@ -751,15 +759,8 @@ struct request *elv_next_request(struct request_queue *q)
                         rq = NULL;
                         break;
                 } else if (ret == BLKPREP_KILL) {
-                        int nr_bytes = rq->hard_nr_sectors << 9;
-
-                        if (!nr_bytes)
-                                nr_bytes = rq->data_len;
-
-                        blkdev_dequeue_request(rq);
                         rq->cmd_flags |= REQ_QUIET;
-                        end_that_request_chunk(rq, 0, nr_bytes);
-                        end_that_request_last(rq, 0);
+                        end_queued_request(rq, 0);
                 } else {
                         printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__,
                                                                 ret);
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index d875673e76cd..4df7d027eb06 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -304,23 +304,6 @@ int blk_queue_ordered(struct request_queue *q, unsigned ordered,
 
 EXPORT_SYMBOL(blk_queue_ordered);
 
-/**
- * blk_queue_issue_flush_fn - set function for issuing a flush
- * @q:     the request queue
- * @iff:   the function to be called issuing the flush
- *
- * Description:
- *   If a driver supports issuing a flush command, the support is notified
- *   to the block layer by defining it through this call.
- *
- **/
-void blk_queue_issue_flush_fn(struct request_queue *q, issue_flush_fn *iff)
-{
-        q->issue_flush_fn = iff;
-}
-
-EXPORT_SYMBOL(blk_queue_issue_flush_fn);
-
 /*
  * Cache flushing for ordered writes handling
  */
@@ -377,10 +360,12 @@ void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
         /*
          * Okay, sequence complete.
          */
-        rq = q->orig_bar_rq;
-        uptodate = q->orderr ? q->orderr : 1;
+        uptodate = 1;
+        if (q->orderr)
+                uptodate = q->orderr;
 
         q->ordseq = 0;
+        rq = q->orig_bar_rq;
 
         end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
         end_that_request_last(rq, uptodate);
@@ -445,7 +430,8 @@ static inline struct request *start_ordered(struct request_queue *q,
         rq_init(q, rq);
         if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
                 rq->cmd_flags |= REQ_RW;
-        rq->cmd_flags |= q->ordered & QUEUE_ORDERED_FUA ? REQ_FUA : 0;
+        if (q->ordered & QUEUE_ORDERED_FUA)
+                rq->cmd_flags |= REQ_FUA;
         rq->elevator_private = NULL;
         rq->elevator_private2 = NULL;
         init_request_from_bio(rq, q->orig_bar_rq->bio);
@@ -455,9 +441,12 @@ static inline struct request *start_ordered(struct request_queue *q,
          * Queue ordered sequence.  As we stack them at the head, we
          * need to queue in reverse order.  Note that we rely on that
          * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
-         * request gets inbetween ordered sequence.
+         * request gets inbetween ordered sequence. If this request is
+         * an empty barrier, we don't need to do a postflush ever since
+         * there will be no data written between the pre and post flush.
+         * Hence a single flush will suffice.
          */
-        if (q->ordered & QUEUE_ORDERED_POSTFLUSH)
+        if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
                 queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
         else
                 q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
@@ -481,7 +470,7 @@ static inline struct request *start_ordered(struct request_queue *q,
 int blk_do_ordered(struct request_queue *q, struct request **rqp)
 {
         struct request *rq = *rqp;
-        int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
+        const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
 
         if (!q->ordseq) {
                 if (!is_barrier)
@@ -2660,6 +2649,14 @@ int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
 
 EXPORT_SYMBOL(blk_execute_rq);
 
+static void bio_end_empty_barrier(struct bio *bio, int err)
+{
+        if (err)
+                clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+        complete(bio->bi_private);
+}
+
 /**
  * blkdev_issue_flush - queue a flush
  * @bdev:       blockdev to issue flush for
@@ -2672,7 +2669,10 @@ EXPORT_SYMBOL(blk_execute_rq);
  */
 int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 {
+        DECLARE_COMPLETION_ONSTACK(wait);
         struct request_queue *q;
+        struct bio *bio;
+        int ret;
 
         if (bdev->bd_disk == NULL)
                 return -ENXIO;
@@ -2680,10 +2680,32 @@ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
         q = bdev_get_queue(bdev);
         if (!q)
                 return -ENXIO;
-        if (!q->issue_flush_fn)
-                return -EOPNOTSUPP;
 
-        return q->issue_flush_fn(q, bdev->bd_disk, error_sector);
+        bio = bio_alloc(GFP_KERNEL, 0);
+        if (!bio)
+                return -ENOMEM;
+
+        bio->bi_end_io = bio_end_empty_barrier;
+        bio->bi_private = &wait;
+        bio->bi_bdev = bdev;
+        submit_bio(1 << BIO_RW_BARRIER, bio);
+
+        wait_for_completion(&wait);
+
+        /*
+         * The driver must store the error location in ->bi_sector, if
+         * it supports it. For non-stacked drivers, this should be copied
+         * from rq->sector.
+         */
+        if (error_sector)
+                *error_sector = bio->bi_sector;
+
+        ret = 0;
+        if (!bio_flagged(bio, BIO_UPTODATE))
+                ret = -EIO;
+
+        bio_put(bio);
+        return ret;
 }
 
 EXPORT_SYMBOL(blkdev_issue_flush);
@@ -3051,7 +3073,7 @@ static inline void blk_partition_remap(struct bio *bio)
 {
         struct block_device *bdev = bio->bi_bdev;
 
-        if (bdev != bdev->bd_contains) {
+        if (bio_sectors(bio) && bdev != bdev->bd_contains) {
                 struct hd_struct *p = bdev->bd_part;
                 const int rw = bio_data_dir(bio);
 
@@ -3117,6 +3139,35 @@ static inline int should_fail_request(struct bio *bio)
 
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
+/*
+ * Check whether this bio extends beyond the end of the device.
+ */
+static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
+{
+        sector_t maxsector;
+
+        if (!nr_sectors)
+                return 0;
+
+        /* Test device or partition size, when known. */
+        maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+        if (maxsector) {
+                sector_t sector = bio->bi_sector;
+
+                if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
+                        /*
+                         * This may well happen - the kernel calls bread()
+                         * without checking the size of the device, e.g., when
+                         * mounting a device.
+                         */
+                        handle_bad_sector(bio);
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
 /**
  * generic_make_request: hand a buffer to its device driver for I/O
  * @bio:  The bio describing the location in memory and on the device.
@@ -3144,27 +3195,14 @@ static inline int should_fail_request(struct bio *bio)
 static inline void __generic_make_request(struct bio *bio)
 {
         struct request_queue *q;
-        sector_t maxsector;
         sector_t old_sector;
         int ret, nr_sectors = bio_sectors(bio);
         dev_t old_dev;
 
         might_sleep();
-        /* Test device or partition size, when known. */
-        maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
-        if (maxsector) {
-                sector_t sector = bio->bi_sector;
 
-                if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
-                        /*
-                         * This may well happen - the kernel calls bread()
-                         * without checking the size of the device, e.g., when
-                         * mounting a device.
-                         */
-                        handle_bad_sector(bio);
-                        goto end_io;
-                }
-        }
+        if (bio_check_eod(bio, nr_sectors))
+                goto end_io;
 
         /*
          * Resolve the mapping until finished. (drivers are
@@ -3191,7 +3229,7 @@ end_io:
                         break;
                 }
 
-                if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) {
+                if (unlikely(nr_sectors > q->max_hw_sectors)) {
                         printk("bio too big device %s (%u > %u)\n", 
                                 bdevname(bio->bi_bdev, b),
                                 bio_sectors(bio),
@@ -3212,7 +3250,7 @@ end_io:
                 blk_partition_remap(bio);
 
                 if (old_sector != -1)
-                        blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, 
+                        blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
                                             old_sector);
 
                 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
@@ -3220,21 +3258,8 @@ end_io:
                 old_sector = bio->bi_sector;
                 old_dev = bio->bi_bdev->bd_dev;
 
-                maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
-                if (maxsector) {
-                        sector_t sector = bio->bi_sector;
-
-                        if (maxsector < nr_sectors ||
-                                        maxsector - nr_sectors < sector) {
-                                /*
-                                 * This may well happen - partitions are not
-                                 * checked to make sure they are within the size
-                                 * of the whole device.
-                                 */
-                                handle_bad_sector(bio);
-                                goto end_io;
-                        }
-                }
+                if (bio_check_eod(bio, nr_sectors))
+                        goto end_io;
 
                 ret = q->make_request_fn(q, bio);
         } while (ret);
@@ -3307,23 +3332,32 @@ void submit_bio(int rw, struct bio *bio)
 {
         int count = bio_sectors(bio);
 
-        BIO_BUG_ON(!bio->bi_size);
-        BIO_BUG_ON(!bio->bi_io_vec);
         bio->bi_rw |= rw;
-        if (rw & WRITE) {
-                count_vm_events(PGPGOUT, count);
-        } else {
-                task_io_account_read(bio->bi_size);
-                count_vm_events(PGPGIN, count);
-        }
 
-        if (unlikely(block_dump)) {
-                char b[BDEVNAME_SIZE];
-                printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
-                        current->comm, current->pid,
-                        (rw & WRITE) ? "WRITE" : "READ",
-                        (unsigned long long)bio->bi_sector,
-                        bdevname(bio->bi_bdev,b));
+        /*
+         * If it's a regular read/write or a barrier with data attached,
+         * go through the normal accounting stuff before submission.
+         */
+        if (!bio_empty_barrier(bio)) {
+
+                BIO_BUG_ON(!bio->bi_size);
+                BIO_BUG_ON(!bio->bi_io_vec);
+
+                if (rw & WRITE) {
+                        count_vm_events(PGPGOUT, count);
+                } else {
+                        task_io_account_read(bio->bi_size);
+                        count_vm_events(PGPGIN, count);
+                }
+
+                if (unlikely(block_dump)) {
+                        char b[BDEVNAME_SIZE];
+                        printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
+                                current->comm, current->pid,
+                                (rw & WRITE) ? "WRITE" : "READ",
+                                (unsigned long long)bio->bi_sector,
+                                bdevname(bio->bi_bdev,b));
+                }
         }
 
         generic_make_request(bio);
@@ -3399,6 +3433,14 @@ static int __end_that_request_first(struct request *req, int uptodate,
         while ((bio = req->bio) != NULL) {
                 int nbytes;
 
+                /*
+                 * For an empty barrier request, the low level driver must
+                 * store a potential error location in ->sector. We pass
+                 * that back up in ->bi_sector.
+                 */
+                if (blk_empty_barrier(req))
+                        bio->bi_sector = req->sector;
+
                 if (nr_bytes >= bio->bi_size) {
                         req->bio = bio->bi_next;
                         nbytes = bio->bi_size;
@@ -3564,7 +3606,7 @@ static struct notifier_block blk_cpu_notifier __cpuinitdata = {
  * Description:
  *     Ends all I/O on a request. It does not handle partial completions,
  *     unless the driver actually implements this in its completion callback
- *     through requeueing. Theh actual completion happens out-of-order,
+ *     through requeueing. The actual completion happens out-of-order,
  *     through a softirq handler. The user must have registered a completion
  *     callback through blk_queue_softirq_done().
  **/
@@ -3627,15 +3669,83 @@ void end_that_request_last(struct request *req, int uptodate)
 
 EXPORT_SYMBOL(end_that_request_last);
 
-void end_request(struct request *req, int uptodate)
+static inline void __end_request(struct request *rq, int uptodate,
+                                 unsigned int nr_bytes, int dequeue)
 {
-        if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) {
-                add_disk_randomness(req->rq_disk);
-                blkdev_dequeue_request(req);
-                end_that_request_last(req, uptodate);
+        if (!end_that_request_chunk(rq, uptodate, nr_bytes)) {
+                if (dequeue)
+                        blkdev_dequeue_request(rq);
+                add_disk_randomness(rq->rq_disk);
+                end_that_request_last(rq, uptodate);
         }
 }
 
+static unsigned int rq_byte_size(struct request *rq)
+{
+        if (blk_fs_request(rq))
+                return rq->hard_nr_sectors << 9;
+
+        return rq->data_len;
+}
+
+/**
+ * end_queued_request - end all I/O on a queued request
+ * @rq:         the request being processed
+ * @uptodate:   error value or 0/1 uptodate flag
+ *
+ * Description:
+ *     Ends all I/O on a request, and removes it from the block layer queues.
+ *     Not suitable for normal IO completion, unless the driver still has
+ *     the request attached to the block layer.
+ *
+ **/
+void end_queued_request(struct request *rq, int uptodate)
+{
+        __end_request(rq, uptodate, rq_byte_size(rq), 1);
+}
+EXPORT_SYMBOL(end_queued_request);
+
+/**
+ * end_dequeued_request - end all I/O on a dequeued request
+ * @rq:         the request being processed
+ * @uptodate:   error value or 0/1 uptodate flag
+ *
+ * Description:
+ *     Ends all I/O on a request. The request must already have been
+ *     dequeued using blkdev_dequeue_request(), as is normally the case
+ *     for most drivers.
+ *
+ **/
+void end_dequeued_request(struct request *rq, int uptodate)
+{
+        __end_request(rq, uptodate, rq_byte_size(rq), 0);
+}
+EXPORT_SYMBOL(end_dequeued_request);
+
+
+/**
+ * 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
+ *
+ * Description:
+ *     Ends I/O on the current segment of a request. If that is the only
+ *     remaining segment, the request is also completed and freed.
+ *
+ *     This is a remnant of how older block drivers handled IO completions.
+ *     Modern drivers typically end IO on the full request in one go, unless
+ *     they have a residual value to account for. For that case this function
+ *     isn't really useful, unless the residual just happens to be the
+ *     full current segment. In other words, don't use this function in new
+ *     code. Either use end_request_completely(), or the
+ *     end_that_request_chunk() (along with end_that_request_last()) for
+ *     partial completions.
+ *
+ **/
+void end_request(struct request *req, int uptodate)
+{
+        __end_request(req, uptodate, req->hard_cur_sectors << 9, 1);
+}
 EXPORT_SYMBOL(end_request);
 
 static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 540bf3676985..a8130a4ad6d4 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1133,16 +1133,21 @@ static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
          * Schedule reads for missing parts of the packet.
          */
         for (f = 0; f < pkt->frames; f++) {
+                struct bio_vec *vec;
+
                 int p, offset;
                 if (written[f])
                         continue;
                 bio = pkt->r_bios[f];
+                vec = bio->bi_io_vec;
                 bio_init(bio);
                 bio->bi_max_vecs = 1;
                 bio->bi_sector = pkt->sector + f * (CD_FRAMESIZE >> 9);
                 bio->bi_bdev = pd->bdev;
                 bio->bi_end_io = pkt_end_io_read;
                 bio->bi_private = pkt;
+                bio->bi_io_vec = vec;
+                bio->bi_destructor = pkt_bio_destructor;
 
                 p = (f * CD_FRAMESIZE) / PAGE_SIZE;
                 offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
@@ -1439,6 +1444,8 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
         pkt->w_bio->bi_bdev = pd->bdev;
         pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
         pkt->w_bio->bi_private = pkt;
+        pkt->w_bio->bi_io_vec = bvec;
+        pkt->w_bio->bi_destructor = pkt_bio_destructor;
         for (f = 0; f < pkt->frames; f++)
                 if (!bio_add_page(pkt->w_bio, bvec[f].bv_page, CD_FRAMESIZE, bvec[f].bv_offset))
                         BUG();
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 06d0552cf49c..e354bfc070e1 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -414,26 +414,6 @@ static void ps3disk_prepare_flush(struct request_queue *q, struct request *req)
         req->cmd_type = REQ_TYPE_FLUSH;
 }
 
-static int ps3disk_issue_flush(struct request_queue *q, struct gendisk *gendisk,
-                               sector_t *sector)
-{
-        struct ps3_storage_device *dev = q->queuedata;
-        struct request *req;
-        int res;
-
-        dev_dbg(&dev->sbd.core, "%s:%u\n", __func__, __LINE__);
-
-        req = blk_get_request(q, WRITE, __GFP_WAIT);
-        ps3disk_prepare_flush(q, req);
-        res = blk_execute_rq(q, gendisk, req, 0);
-        if (res)
-                dev_err(&dev->sbd.core, "%s:%u: flush request failed %d\n",
-                        __func__, __LINE__, res);
-        blk_put_request(req);
-        return res;
-}
-
-
 static unsigned long ps3disk_mask;
 
 static DEFINE_MUTEX(ps3disk_mask_mutex);
@@ -506,7 +486,6 @@ static int __devinit ps3disk_probe(struct ps3_system_bus_device *_dev)
         blk_queue_dma_alignment(queue, dev->blk_size-1);
         blk_queue_hardsect_size(queue, dev->blk_size);
 
-        blk_queue_issue_flush_fn(queue, ps3disk_issue_flush);
         blk_queue_ordered(queue, QUEUE_ORDERED_DRAIN_FLUSH,
                           ps3disk_prepare_flush);
 
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 4754769eda97..92177ca48b4d 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -716,32 +716,6 @@ static void idedisk_prepare_flush(struct request_queue *q, struct request *rq)
         rq->buffer = rq->cmd;
 }
 
-static int idedisk_issue_flush(struct request_queue *q, struct gendisk *disk,
-                               sector_t *error_sector)
-{
-        ide_drive_t *drive = q->queuedata;
-        struct request *rq;
-        int ret;
-
-        if (!drive->wcache)
-                return 0;
-
-        rq = blk_get_request(q, WRITE, __GFP_WAIT);
-
-        idedisk_prepare_flush(q, rq);
-
-        ret = blk_execute_rq(q, disk, rq, 0);
-
-        /*
-         * if we failed and caller wants error offset, get it
-         */
-        if (ret && error_sector)
-                *error_sector = ide_get_error_location(drive, rq->cmd);
-
-        blk_put_request(rq);
-        return ret;
-}
-
 /*
  * This is tightly woven into the driver->do_special can not touch.
  * DON'T do it again until a total personality rewrite is committed.
@@ -781,7 +755,6 @@ static void update_ordered(ide_drive_t *drive)
         struct hd_driveid *id = drive->id;
         unsigned ordered = QUEUE_ORDERED_NONE;
         prepare_flush_fn *prep_fn = NULL;
-        issue_flush_fn *issue_fn = NULL;
 
         if (drive->wcache) {
                 unsigned long long capacity;
@@ -805,13 +778,11 @@ static void update_ordered(ide_drive_t *drive)
                 if (barrier) {
                         ordered = QUEUE_ORDERED_DRAIN_FLUSH;
                         prep_fn = idedisk_prepare_flush;
-                        issue_fn = idedisk_issue_flush;
                 }
         } else
                 ordered = QUEUE_ORDERED_DRAIN;
 
         blk_queue_ordered(drive->queue, ordered, prep_fn);
-        blk_queue_issue_flush_fn(drive->queue, issue_fn);
 }
 
 static int write_cache(ide_drive_t *drive, int arg)
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 4cece930114c..f36ff5962af6 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -322,41 +322,6 @@ static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
         spin_unlock_irqrestore(&ide_lock, flags);
 }
 
-/*
- * FIXME: probably move this somewhere else, name is bad too :)
- */
-u64 ide_get_error_location(ide_drive_t *drive, char *args)
-{
-        u32 high, low;
-        u8 hcyl, lcyl, sect;
-        u64 sector;
-
-        high = 0;
-        hcyl = args[5];
-        lcyl = args[4];
-        sect = args[3];
-
-        if (ide_id_has_flush_cache_ext(drive->id)) {
-                low = (hcyl << 16) | (lcyl << 8) | sect;
-                HWIF(drive)->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
-                high = ide_read_24(drive);
-        } else {
-                u8 cur = HWIF(drive)->INB(IDE_SELECT_REG);
-                if (cur & 0x40) {
-                        high = cur & 0xf;
-                        low = (hcyl << 16) | (lcyl << 8) | sect;
-                } else {
-                        low = hcyl * drive->head * drive->sect;
-                        low += lcyl * drive->sect;
-                        low += sect - 1;
-                }
-        }
-
-        sector = ((u64) high << 24) | low;
-        return sector;
-}
-EXPORT_SYMBOL(ide_get_error_location);
-
 /**
  *      ide_end_drive_cmd       -       end an explicit drive command
  *      @drive: command 
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 2bcde5798b5a..fbe477bb2c68 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -999,33 +999,6 @@ void dm_table_unplug_all(struct dm_table *t)
         }
 }
 
-int dm_table_flush_all(struct dm_table *t)
-{
-        struct list_head *d, *devices = dm_table_get_devices(t);
-        int ret = 0;
-        unsigned i;
-
-        for (i = 0; i < t->num_targets; i++)
-                if (t->targets[i].type->flush)
-                        t->targets[i].type->flush(&t->targets[i]);
-
-        for (d = devices->next; d != devices; d = d->next) {
-                struct dm_dev *dd = list_entry(d, struct dm_dev, list);
-                struct request_queue *q = bdev_get_queue(dd->bdev);
-                int err;
-
-                if (!q->issue_flush_fn)
-                        err = -EOPNOTSUPP;
-                else
-                        err = q->issue_flush_fn(q, dd->bdev->bd_disk, NULL);
-
-                if (!ret)
-                        ret = err;
-        }
-
-        return ret;
-}
-
 struct mapped_device *dm_table_get_md(struct dm_table *t)
 {
         dm_get(t->md);
@@ -1043,4 +1016,3 @@ EXPORT_SYMBOL(dm_table_get_md);
 EXPORT_SYMBOL(dm_table_put);
 EXPORT_SYMBOL(dm_table_get);
 EXPORT_SYMBOL(dm_table_unplug_all);
-EXPORT_SYMBOL(dm_table_flush_all);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 167765c47747..d837d37f6209 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -840,21 +840,6 @@ static int dm_request(struct request_queue *q, struct bio *bio)
         return 0;
 }
 
-static int dm_flush_all(struct request_queue *q, struct gendisk *disk,
-                        sector_t *error_sector)
-{
-        struct mapped_device *md = q->queuedata;
-        struct dm_table *map = dm_get_table(md);
-        int ret = -ENXIO;
-
-        if (map) {
-                ret = dm_table_flush_all(map);
-                dm_table_put(map);
-        }
-
-        return ret;
-}
-
 static void dm_unplug_all(struct request_queue *q)
 {
         struct mapped_device *md = q->queuedata;
@@ -1003,7 +988,6 @@ static struct mapped_device *alloc_dev(int minor)
         blk_queue_make_request(md->queue, dm_request);
         blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
         md->queue->unplug_fn = dm_unplug_all;
-        md->queue->issue_flush_fn = dm_flush_all;
 
         md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
         if (!md->io_pool)
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 462ee652a890..4b3faa45277e 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -111,7 +111,6 @@ void dm_table_postsuspend_targets(struct dm_table *t);
 int dm_table_resume_targets(struct dm_table *t);
 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
 void dm_table_unplug_all(struct dm_table *t);
-int dm_table_flush_all(struct dm_table *t);
 
 /*-----------------------------------------------------------------
  * A registry of target types.
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 550148770bb2..56a11f6c127b 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -92,25 +92,6 @@ static void linear_unplug(struct request_queue *q)
         }
 }
 
-static int linear_issue_flush(struct request_queue *q, struct gendisk *disk,
-                              sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        linear_conf_t *conf = mddev_to_conf(mddev);
-        int i, ret = 0;
-
-        for (i=0; i < mddev->raid_disks && ret == 0; i++) {
-                struct block_device *bdev = conf->disks[i].rdev->bdev;
-                struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                if (!r_queue->issue_flush_fn)
-                        ret = -EOPNOTSUPP;
-                else
-                        ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
-        }
-        return ret;
-}
-
 static int linear_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -279,7 +260,6 @@ static int linear_run (mddev_t *mddev)
 
         blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
         mddev->queue->unplug_fn = linear_unplug;
-        mddev->queue->issue_flush_fn = linear_issue_flush;
         mddev->queue->backing_dev_info.congested_fn = linear_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
         return 0;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index acf1b81b47cb..0dc563d76b39 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3463,7 +3463,6 @@ static int do_md_stop(mddev_t * mddev, int mode)
                         mddev->pers->stop(mddev);
                         mddev->queue->merge_bvec_fn = NULL;
                         mddev->queue->unplug_fn = NULL;
-                        mddev->queue->issue_flush_fn = NULL;
                         mddev->queue->backing_dev_info.congested_fn = NULL;
                         if (mddev->pers->sync_request)
                                 sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index f2a63f394ad9..b35731cceac6 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -194,35 +194,6 @@ static void multipath_status (struct seq_file *seq, mddev_t *mddev)
         seq_printf (seq, "]");
 }
 
-static int multipath_issue_flush(struct request_queue *q, struct gendisk *disk,
-                                 sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        multipath_conf_t *conf = mddev_to_conf(mddev);
-        int i, ret = 0;
-
-        rcu_read_lock();
-        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
-                if (rdev && !test_bit(Faulty, &rdev->flags)) {
-                        struct block_device *bdev = rdev->bdev;
-                        struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                        if (!r_queue->issue_flush_fn)
-                                ret = -EOPNOTSUPP;
-                        else {
-                                atomic_inc(&rdev->nr_pending);
-                                rcu_read_unlock();
-                                ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                              error_sector);
-                                rdev_dec_pending(rdev, mddev);
-                                rcu_read_lock();
-                        }
-                }
-        }
-        rcu_read_unlock();
-        return ret;
-}
 static int multipath_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -527,7 +498,6 @@ static int multipath_run (mddev_t *mddev)
         mddev->array_size = mddev->size;
 
         mddev->queue->unplug_fn = multipath_unplug;
-        mddev->queue->issue_flush_fn = multipath_issue_flush;
         mddev->queue->backing_dev_info.congested_fn = multipath_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index ef0da2d84959..e79e1a538d44 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -40,26 +40,6 @@ static void raid0_unplug(struct request_queue *q)
         }
 }
 
-static int raid0_issue_flush(struct request_queue *q, struct gendisk *disk,
-                             sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        raid0_conf_t *conf = mddev_to_conf(mddev);
-        mdk_rdev_t **devlist = conf->strip_zone[0].dev;
-        int i, ret = 0;
-
-        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                struct block_device *bdev = devlist[i]->bdev;
-                struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                if (!r_queue->issue_flush_fn)
-                        ret = -EOPNOTSUPP;
-                else
-                        ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
-        }
-        return ret;
-}
-
 static int raid0_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -250,7 +230,6 @@ static int create_strip_zones (mddev_t *mddev)
 
         mddev->queue->unplug_fn = raid0_unplug;
 
-        mddev->queue->issue_flush_fn = raid0_issue_flush;
         mddev->queue->backing_dev_info.congested_fn = raid0_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6d03bea6fa58..0bcefad82413 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -567,36 +567,6 @@ static void raid1_unplug(struct request_queue *q)
         md_wakeup_thread(mddev->thread);
 }
 
-static int raid1_issue_flush(struct request_queue *q, struct gendisk *disk,
-                             sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        conf_t *conf = mddev_to_conf(mddev);
-        int i, ret = 0;
-
-        rcu_read_lock();
-        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-                if (rdev && !test_bit(Faulty, &rdev->flags)) {
-                        struct block_device *bdev = rdev->bdev;
-                        struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                        if (!r_queue->issue_flush_fn)
-                                ret = -EOPNOTSUPP;
-                        else {
-                                atomic_inc(&rdev->nr_pending);
-                                rcu_read_unlock();
-                                ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                              error_sector);
-                                rdev_dec_pending(rdev, mddev);
-                                rcu_read_lock();
-                        }
-                }
-        }
-        rcu_read_unlock();
-        return ret;
-}
-
 static int raid1_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -1997,7 +1967,6 @@ static int run(mddev_t *mddev)
         mddev->array_size = mddev->size;
 
         mddev->queue->unplug_fn = raid1_unplug;
-        mddev->queue->issue_flush_fn = raid1_issue_flush;
         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 25a96c42bdb0..fc6607acb6e4 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -611,36 +611,6 @@ static void raid10_unplug(struct request_queue *q)
         md_wakeup_thread(mddev->thread);
 }
 
-static int raid10_issue_flush(struct request_queue *q, struct gendisk *disk,
-                             sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        conf_t *conf = mddev_to_conf(mddev);
-        int i, ret = 0;
-
-        rcu_read_lock();
-        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-                if (rdev && !test_bit(Faulty, &rdev->flags)) {
-                        struct block_device *bdev = rdev->bdev;
-                        struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                        if (!r_queue->issue_flush_fn)
-                                ret = -EOPNOTSUPP;
-                        else {
-                                atomic_inc(&rdev->nr_pending);
-                                rcu_read_unlock();
-                                ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                              error_sector);
-                                rdev_dec_pending(rdev, mddev);
-                                rcu_read_lock();
-                        }
-                }
-        }
-        rcu_read_unlock();
-        return ret;
-}
-
 static int raid10_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -2118,7 +2088,6 @@ static int run(mddev_t *mddev)
         mddev->resync_max_sectors = size << conf->chunk_shift;
 
         mddev->queue->unplug_fn = raid10_unplug;
-        mddev->queue->issue_flush_fn = raid10_issue_flush;
         mddev->queue->backing_dev_info.congested_fn = raid10_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index caaca9e178bc..8ee181a01f52 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3204,36 +3204,6 @@ static void raid5_unplug_device(struct request_queue *q)
         unplug_slaves(mddev);
 }
 
-static int raid5_issue_flush(struct request_queue *q, struct gendisk *disk,
-                             sector_t *error_sector)
-{
-        mddev_t *mddev = q->queuedata;
-        raid5_conf_t *conf = mddev_to_conf(mddev);
-        int i, ret = 0;
-
-        rcu_read_lock();
-        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-                mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
-                if (rdev && !test_bit(Faulty, &rdev->flags)) {
-                        struct block_device *bdev = rdev->bdev;
-                        struct request_queue *r_queue = bdev_get_queue(bdev);
-
-                        if (!r_queue->issue_flush_fn)
-                                ret = -EOPNOTSUPP;
-                        else {
-                                atomic_inc(&rdev->nr_pending);
-                                rcu_read_unlock();
-                                ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                              error_sector);
-                                rdev_dec_pending(rdev, mddev);
-                                rcu_read_lock();
-                        }
-                }
-        }
-        rcu_read_unlock();
-        return ret;
-}
-
 static int raid5_congested(void *data, int bits)
 {
         mddev_t *mddev = data;
@@ -4263,7 +4233,6 @@ static int run(mddev_t *mddev)
                        mdname(mddev));
 
         mddev->queue->unplug_fn = raid5_unplug_device;
-        mddev->queue->issue_flush_fn = raid5_issue_flush;
         mddev->queue->backing_dev_info.congested_data = mddev;
         mddev->queue->backing_dev_info.congested_fn = raid5_congested;
 
diff --git a/drivers/message/i2o/i2o_block.c b/drivers/message/i2o/i2o_block.c
index 50b2c7334410..d602ba6d5417 100644
--- a/drivers/message/i2o/i2o_block.c
+++ b/drivers/message/i2o/i2o_block.c
@@ -149,29 +149,6 @@ static int i2o_block_device_flush(struct i2o_device *dev)
 };
 
 /**
- *      i2o_block_issue_flush - device-flush interface for block-layer
- *      @queue: the request queue of the device which should be flushed
- *      @disk: gendisk
- *      @error_sector: error offset
- *
- *      Helper function to provide flush functionality to block-layer.
- *
- *      Returns 0 on success or negative error code on failure.
- */
-
-static int i2o_block_issue_flush(struct request_queue * queue, struct gendisk *disk,
-                                 sector_t * error_sector)
-{
-        struct i2o_block_device *i2o_blk_dev = queue->queuedata;
-        int rc = -ENODEV;
-
-        if (likely(i2o_blk_dev))
-                rc = i2o_block_device_flush(i2o_blk_dev->i2o_dev);
-
-        return rc;
-}
-
-/**
  *      i2o_block_device_mount - Mount (load) the media of device dev
  *      @dev: I2O device which should receive the mount request
  *      @media_id: Media Identifier
@@ -1009,7 +986,6 @@ static struct i2o_block_device *i2o_block_device_alloc(void)
         }
 
         blk_queue_prep_rq(queue, i2o_block_prep_req_fn);
-        blk_queue_issue_flush_fn(queue, i2o_block_issue_flush);
 
         gd->major = I2O_MAJOR;
         gd->queue = queue;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0a3a528212c2..69f542c4923c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -826,27 +826,6 @@ static int sd_sync_cache(struct scsi_disk *sdkp)
         return 0;
 }
 
-static int sd_issue_flush(struct request_queue *q, struct gendisk *disk,
-                          sector_t *error_sector)
-{
-        int ret = 0;
-        struct scsi_device *sdp = q->queuedata;
-        struct scsi_disk *sdkp;
-
-        if (sdp->sdev_state != SDEV_RUNNING)
-                return -ENXIO;
-
-        sdkp = scsi_disk_get_from_dev(&sdp->sdev_gendev);
-
-        if (!sdkp)
-               return -ENODEV;
-
-        if (sdkp->WCE)
-                ret = sd_sync_cache(sdkp);
-        scsi_disk_put(sdkp);
-        return ret;
-}
-
 static void sd_prepare_flush(struct request_queue *q, struct request *rq)
 {
         memset(rq->cmd, 0, sizeof(rq->cmd));
@@ -1697,7 +1676,6 @@ static int sd_probe(struct device *dev)
         sd_revalidate_disk(gd);
 
         blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
-        blk_queue_issue_flush_fn(sdp->request_queue, sd_issue_flush);
 
         gd->driverfs_dev = &sdp->sdev_gendev;
         gd->flags = GENHD_FL_DRIVERFS;
diff --git a/fs/bio.c b/fs/bio.c
index 5f604f269dfa..d59ddbf79626 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -109,11 +109,14 @@ static inline struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned lon
 
 void bio_free(struct bio *bio, struct bio_set *bio_set)
 {
-        const int pool_idx = BIO_POOL_IDX(bio);
+        if (bio->bi_io_vec) {
+                const int pool_idx = BIO_POOL_IDX(bio);
 
-        BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
+                BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
+
+                mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
+        }
 
-        mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
         mempool_free(bio, bio_set->bio_pool);
 }
 
@@ -127,21 +130,9 @@ static void bio_fs_destructor(struct bio *bio)
 
 void bio_init(struct bio *bio)
 {
-        bio->bi_next = NULL;
-        bio->bi_bdev = NULL;
+        memset(bio, 0, sizeof(*bio));
         bio->bi_flags = 1 << BIO_UPTODATE;
-        bio->bi_rw = 0;
-        bio->bi_vcnt = 0;
-        bio->bi_idx = 0;
-        bio->bi_phys_segments = 0;
-        bio->bi_hw_segments = 0;
-        bio->bi_hw_front_size = 0;
-        bio->bi_hw_back_size = 0;
-        bio->bi_size = 0;
-        bio->bi_max_vecs = 0;
-        bio->bi_end_io = NULL;
         atomic_set(&bio->bi_cnt, 1);
-        bio->bi_private = NULL;
 }
 
 /**
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 089a8bc55dd4..4da441337d6e 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -176,13 +176,28 @@ struct bio {
 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
-#define bio_cur_sectors(bio)    (bio_iovec(bio)->bv_len >> 9)
-#define bio_data(bio)           (page_address(bio_page((bio))) + bio_offset((bio)))
 #define bio_barrier(bio)        ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
 #define bio_sync(bio)           ((bio)->bi_rw & (1 << BIO_RW_SYNC))
 #define bio_failfast(bio)       ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
 #define bio_rw_ahead(bio)       ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
 #define bio_rw_meta(bio)        ((bio)->bi_rw & (1 << BIO_RW_META))
+#define bio_empty_barrier(bio)  (bio_barrier(bio) && !(bio)->bi_size)
+
+static inline unsigned int bio_cur_sectors(struct bio *bio)
+{
+        if (bio->bi_vcnt)
+                return bio_iovec(bio)->bv_len >> 9;
+
+        return 0;
+}
+
+static inline void *bio_data(struct bio *bio)
+{
+        if (bio->bi_vcnt)
+                return page_address(bio_page(bio)) + bio_offset(bio);
+
+        return NULL;
+}
 
 /*
  * will die
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5ed888b04b29..bbf906a0b419 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -330,7 +330,6 @@ typedef void (unplug_fn) (struct request_queue *);
 
 struct bio_vec;
 typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
-typedef int (issue_flush_fn) (struct request_queue *, struct gendisk *, sector_t *);
 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 typedef void (softirq_done_fn)(struct request *);
 
@@ -368,7 +367,6 @@ struct request_queue
         prep_rq_fn              *prep_rq_fn;
         unplug_fn               *unplug_fn;
         merge_bvec_fn           *merge_bvec_fn;
-        issue_flush_fn          *issue_flush_fn;
         prepare_flush_fn        *prepare_flush_fn;
         softirq_done_fn         *softirq_done_fn;
 
@@ -540,6 +538,7 @@ enum {
 #define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 #define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
+#define blk_empty_barrier(rq)   (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
 
 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 
@@ -729,7 +728,9 @@ static inline void blk_run_address_space(struct address_space *mapping)
 extern int end_that_request_first(struct request *, int, int);
 extern int end_that_request_chunk(struct request *, int, int);
 extern void end_that_request_last(struct request *, int);
-extern void end_request(struct request *req, int uptodate);
+extern void end_request(struct request *, int);
+extern void end_queued_request(struct request *, int);
+extern void end_dequeued_request(struct request *, int);
 extern void blk_complete_request(struct request *);
 
 /*
@@ -767,7 +768,6 @@ extern void blk_queue_dma_alignment(struct request_queue *, int);
 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
-extern void blk_queue_issue_flush_fn(struct request_queue *, issue_flush_fn *);
 extern int blk_do_ordered(struct request_queue *, struct request **);
 extern unsigned blk_ordered_cur_seq(struct request_queue *);
 extern unsigned blk_ordered_req_seq(struct request *);
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 02a27e8cbad2..234fa3df24f6 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1093,11 +1093,6 @@ extern ide_startstop_t ide_do_reset (ide_drive_t *);
 extern void ide_init_drive_cmd (struct request *rq);
 
 /*
- * this function returns error location sector offset in case of a write error
- */
-extern u64 ide_get_error_location(ide_drive_t *, char *);
-
-/*
  * "action" parameter type for ide_do_drive_cmd() below.
  */
 typedef enum {
diff --git a/mm/bounce.c b/mm/bounce.c
index 3b549bf31f7d..b6d2d0f1019b 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -265,6 +265,12 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
         mempool_t *pool;
 
         /*
+         * Data-less bio, nothing to bounce
+         */
+        if (bio_empty_barrier(*bio_orig))
+                return;
+
+        /*
          * for non-isa bounce case, just check if the bounce pfn is equal
          * to or bigger than the highest pfn in the system -- in that case,
          * don't waste time iterating over bio segments