block: convert blkdev_issue_flush() to use empty barriers
authorJens Axboe <jens.axboe@oracle.com>
Tue, 16 Oct 2007 09:05:02 +0000 (11:05 +0200)
committerJens Axboe <jens.axboe@oracle.com>
Tue, 16 Oct 2007 09:05:02 +0000 (11:05 +0200)
Then we can get rid of ->issue_flush_fn() and all the driver private
implementations of that.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
16 files changed:
block/ll_rw_blk.c
drivers/block/ps3disk.c
drivers/ide/ide-disk.c
drivers/md/dm-table.c
drivers/md/dm.c
drivers/md/dm.h
drivers/md/linear.c
drivers/md/md.c
drivers/md/multipath.c
drivers/md/raid0.c
drivers/md/raid1.c
drivers/md/raid10.c
drivers/md/raid5.c
drivers/message/i2o/i2o_block.c
drivers/scsi/sd.c
include/linux/blkdev.h

index 4fde3a3..4df7d02 100644 (file)
@@ -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
  */
@@ -2666,6 +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
@@ -2678,7 +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;
@@ -2686,10 +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);
index 06d0552..e354bfc 100644 (file)
@@ -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);
 
index 4754769..92177ca 100644 (file)
@@ -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)
index 2bcde57..fbe477b 100644 (file)
@@ -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);
index 167765c..d837d37 100644 (file)
@@ -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)
index 462ee65..4b3faa4 100644 (file)
@@ -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.
index 5501487..56a11f6 100644 (file)
@@ -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;
index acf1b81..0dc563d 100644 (file)
@@ -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);
index f2a63f3..b35731c 100644 (file)
@@ -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;
 
index ef0da2d..e79e1a5 100644 (file)
@@ -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;
 
index 6d03bea..0bcefad 100644 (file)
@@ -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;
 
index 25a96c4..fc6607a 100644 (file)
@@ -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;
 
index caaca9e..8ee181a 100644 (file)
@@ -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;
 
index 50b2c73..d602ba6 100644 (file)
@@ -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;
index 0a3a528..69f542c 100644 (file)
@@ -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;
index fb2ff74..bbf906a 100644 (file)
@@ -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;
 
@@ -770,7 +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 *);