block: export __make_request

Avoid the hacks need for request based device mappers currently by simply
exporting the symbol instead of trying to get it through the back door.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

3 files changed, 5 insertions, 15 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index b627558c461f..56ef387e7d27 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -38,8 +38,6 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
 
-static int __make_request(struct request_queue *q, struct bio *bio);
-
 /*
  * For the allocated request tables
  */
@@ -1213,7 +1211,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
         blk_rq_bio_prep(req->q, req, bio);
 }
 
-static int __make_request(struct request_queue *q, struct bio *bio)
+int __make_request(struct request_queue *q, struct bio *bio)
 {
         const bool sync = !!(bio->bi_rw & REQ_SYNC);
         struct blk_plug *plug;
@@ -1317,6 +1315,7 @@ out_unlock:
 out:
         return 0;
 }
+EXPORT_SYMBOL_GPL(__make_request);      /* for device mapper only */
 
 /*
  * If bio->bi_dev is a partition, remap the location
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 52b39f335bb3..d8d7b8d9dd28 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -180,9 +180,6 @@ struct mapped_device {
         /* forced geometry settings */
         struct hd_geometry geometry;
 
-        /* For saving the address of __make_request for request based dm */
-        make_request_fn *saved_make_request_fn;
-
         /* sysfs handle */
         struct kobject kobj;
 
@@ -1420,13 +1417,6 @@ static int _dm_request(struct request_queue *q, struct bio *bio)
         return 0;
 }
 
-static int dm_make_request(struct request_queue *q, struct bio *bio)
-{
-        struct mapped_device *md = q->queuedata;
-
-        return md->saved_make_request_fn(q, bio); /* call __make_request() */
-}
-
 static int dm_request_based(struct mapped_device *md)
 {
         return blk_queue_stackable(md->queue);
@@ -1437,7 +1427,7 @@ static int dm_request(struct request_queue *q, struct bio *bio)
         struct mapped_device *md = q->queuedata;
 
         if (dm_request_based(md))
-                return dm_make_request(q, bio);
+                return __make_request(q, bio);
 
         return _dm_request(q, bio);
 }
@@ -2172,7 +2162,6 @@ static int dm_init_request_based_queue(struct mapped_device *md)
                 return 0;
 
         md->queue = q;
-        md->saved_make_request_fn = md->queue->make_request_fn;
         dm_init_md_queue(md);
         blk_queue_softirq_done(md->queue, dm_softirq_done);
         blk_queue_prep_rq(md->queue, dm_prep_fn);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0e67c45b3bc9..e9c3d9b07630 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -675,6 +675,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
                          struct scsi_ioctl_command __user *);
 
+extern int __make_request(struct request_queue *q, struct bio *bio);
+
 /*
  * A queue has just exitted congestion.  Note this in the global counter of
  * congested queues, and wake up anyone who was waiting for requests to be