block: remove support for bio remapping from ->make_request

There is very little benefit in allowing to let a ->make_request
instance update the bios device and sector and loop around it in
__generic_make_request when we can archive the same through calling
generic_make_request from the driver and letting the loop in
generic_make_request handle it.

Note that various drivers got the return value from ->make_request and
returned non-zero values for errors.

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

10 files changed, 53 insertions, 71 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 78b20868bcbc..7b986e77b75e 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1388,7 +1388,7 @@ out:
  * The request function that just remaps the bio built up by
  * dm_merge_bvec.
  */
-static int _dm_request(struct request_queue *q, struct bio *bio)
+static void _dm_request(struct request_queue *q, struct bio *bio)
 {
 	int rw = bio_data_dir(bio);
 	struct mapped_device *md = q->queuedata;
@@ -1409,12 +1409,12 @@ static int _dm_request(struct request_queue *q, struct bio *bio)
 			queue_io(md, bio);
 		else
 			bio_io_error(bio);
-		return 0;
+		return;
 	}
 
 	__split_and_process_bio(md, bio);
 	up_read(&md->io_lock);
-	return 0;
+	return;
 }
 
 static int dm_request_based(struct mapped_device *md)
@@ -1422,14 +1422,14 @@ static int dm_request_based(struct mapped_device *md)
 	return blk_queue_stackable(md->queue);
 }
 
-static int dm_request(struct request_queue *q, struct bio *bio)
+static void dm_request(struct request_queue *q, struct bio *bio)
 {
 	struct mapped_device *md = q->queuedata;
 
 	if (dm_request_based(md))
-		return blk_queue_bio(q, bio);
-
-	return _dm_request(q, bio);
+		blk_queue_bio(q, bio);
+	else
+		_dm_request(q, bio);
 }
 
 void dm_dispatch_request(struct request *rq)
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index 23078dabb6df..5ef304d4341c 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -169,7 +169,7 @@ static void add_sector(conf_t *conf, sector_t start, int mode)
 		conf->nfaults = n+1;
 }
 
-static int make_request(mddev_t *mddev, struct bio *bio)
+static void make_request(mddev_t *mddev, struct bio *bio)
 {
 	conf_t *conf = mddev->private;
 	int failit = 0;
@@ -181,7 +181,7 @@ static int make_request(mddev_t *mddev, struct bio *bio)
 			 * just fail immediately
 			 */
 			bio_endio(bio, -EIO);
-			return 0;
+			return;
 		}
 
 		if (check_sector(conf, bio->bi_sector, bio->bi_sector+(bio->bi_size>>9),
@@ -211,15 +211,15 @@ static int make_request(mddev_t *mddev, struct bio *bio)
 	}
 	if (failit) {
 		struct bio *b = bio_clone_mddev(bio, GFP_NOIO, mddev);
+
 		b->bi_bdev = conf->rdev->bdev;
 		b->bi_private = bio;
 		b->bi_end_io = faulty_fail;
-		generic_make_request(b);
-		return 0;
-	} else {
+		bio = b;
+	} else
 		bio->bi_bdev = conf->rdev->bdev;
-		return 1;
-	}
+
+	generic_make_request(bio);
 }
 
 static void status(struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 6cd2c313e800..c6ee491d98e7 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -264,14 +264,14 @@ static int linear_stop (mddev_t *mddev)
 	return 0;
 }
 
-static int linear_make_request (mddev_t *mddev, struct bio *bio)
+static void linear_make_request (mddev_t *mddev, struct bio *bio)
 {
 	dev_info_t *tmp_dev;
 	sector_t start_sector;
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
-		return 0;
+		return;
 	}
 
 	rcu_read_lock();
@@ -293,7 +293,7 @@ static int linear_make_request (mddev_t *mddev, struct bio *bio)
 		       (unsigned long long)start_sector);
 		rcu_read_unlock();
 		bio_io_error(bio);
-		return 0;
+		return;
 	}
 	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
 		     tmp_dev->end_sector)) {
@@ -307,20 +307,17 @@ static int linear_make_request (mddev_t *mddev, struct bio *bio)
 
 		bp = bio_split(bio, end_sector - bio->bi_sector);
 
-		if (linear_make_request(mddev, &bp->bio1))
-			generic_make_request(&bp->bio1);
-		if (linear_make_request(mddev, &bp->bio2))
-			generic_make_request(&bp->bio2);
+		linear_make_request(mddev, &bp->bio1);
+		linear_make_request(mddev, &bp->bio2);
 		bio_pair_release(bp);
-		return 0;
+		return;
 	}
 		    
 	bio->bi_bdev = tmp_dev->rdev->bdev;
 	bio->bi_sector = bio->bi_sector - start_sector
 		+ tmp_dev->rdev->data_offset;
 	rcu_read_unlock();
-
-	return 1;
+	generic_make_request(bio);
 }
 
 static void linear_status (struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8e221a20f5d9..5c2178562c96 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -330,18 +330,17 @@ static DEFINE_SPINLOCK(all_mddevs_lock);
  * call has finished, the bio has been linked into some internal structure
  * and so is visible to ->quiesce(), so we don't need the refcount any more.
  */
-static int md_make_request(struct request_queue *q, struct bio *bio)
+static void md_make_request(struct request_queue *q, struct bio *bio)
 {
 	const int rw = bio_data_dir(bio);
 	mddev_t *mddev = q->queuedata;
-	int rv;
 	int cpu;
 	unsigned int sectors;
 
 	if (mddev == NULL || mddev->pers == NULL
 	    || !mddev->ready) {
 		bio_io_error(bio);
-		return 0;
+		return;
 	}
 	smp_rmb(); /* Ensure implications of  'active' are visible */
 	rcu_read_lock();
@@ -366,7 +365,7 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
 	 * go away inside make_request
 	 */
 	sectors = bio_sectors(bio);
-	rv = mddev->pers->make_request(mddev, bio);
+	mddev->pers->make_request(mddev, bio);
 
 	cpu = part_stat_lock();
 	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
@@ -375,8 +374,6 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
 
 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
 		wake_up(&mddev->sb_wait);
-
-	return rv;
 }
 
 /* mddev_suspend makes sure no new requests are submitted
@@ -475,8 +472,7 @@ static void md_submit_flush_data(struct work_struct *ws)
 		bio_endio(bio, 0);
 	else {
 		bio->bi_rw &= ~REQ_FLUSH;
-		if (mddev->pers->make_request(mddev, bio))
-			generic_make_request(bio);
+		mddev->pers->make_request(mddev, bio);
 	}
 
 	mddev->flush_bio = NULL;
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 1e586bb4452e..bd47847cf7ca 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -424,7 +424,7 @@ struct mdk_personality
 	int level;
 	struct list_head list;
 	struct module *owner;
-	int (*make_request)(mddev_t *mddev, struct bio *bio);
+	void (*make_request)(mddev_t *mddev, struct bio *bio);
 	int (*run)(mddev_t *mddev);
 	int (*stop)(mddev_t *mddev);
 	void (*status)(struct seq_file *seq, mddev_t *mddev);
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 3535c23af288..407cb5691425 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -106,7 +106,7 @@ static void multipath_end_request(struct bio *bio, int error)
 	rdev_dec_pending(rdev, conf->mddev);
 }
 
-static int multipath_make_request(mddev_t *mddev, struct bio * bio)
+static void multipath_make_request(mddev_t *mddev, struct bio * bio)
 {
 	multipath_conf_t *conf = mddev->private;
 	struct multipath_bh * mp_bh;
@@ -114,7 +114,7 @@ static int multipath_make_request(mddev_t *mddev, struct bio * bio)
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
-		return 0;
+		return;
 	}
 
 	mp_bh = mempool_alloc(conf->pool, GFP_NOIO);
@@ -126,7 +126,7 @@ static int multipath_make_request(mddev_t *mddev, struct bio * bio)
 	if (mp_bh->path < 0) {
 		bio_endio(bio, -EIO);
 		mempool_free(mp_bh, conf->pool);
-		return 0;
+		return;
 	}
 	multipath = conf->multipaths + mp_bh->path;
 
@@ -137,7 +137,7 @@ static int multipath_make_request(mddev_t *mddev, struct bio * bio)
 	mp_bh->bio.bi_end_io = multipath_end_request;
 	mp_bh->bio.bi_private = mp_bh;
 	generic_make_request(&mp_bh->bio);
-	return 0;
+	return;
 }
 
 static void multipath_status (struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index e86bf3682e1e..4066615d61af 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -466,7 +466,7 @@ static inline int is_io_in_chunk_boundary(mddev_t *mddev,
 	}
 }
 
-static int raid0_make_request(mddev_t *mddev, struct bio *bio)
+static void raid0_make_request(mddev_t *mddev, struct bio *bio)
 {
 	unsigned int chunk_sects;
 	sector_t sector_offset;
@@ -475,7 +475,7 @@ static int raid0_make_request(mddev_t *mddev, struct bio *bio)
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
-		return 0;
+		return;
 	}
 
 	chunk_sects = mddev->chunk_sectors;
@@ -495,13 +495,10 @@ static int raid0_make_request(mddev_t *mddev, struct bio *bio)
 		else
 			bp = bio_split(bio, chunk_sects -
 				       sector_div(sector, chunk_sects));
-		if (raid0_make_request(mddev, &bp->bio1))
-			generic_make_request(&bp->bio1);
-		if (raid0_make_request(mddev, &bp->bio2))
-			generic_make_request(&bp->bio2);
-
+		raid0_make_request(mddev, &bp->bio1);
+		raid0_make_request(mddev, &bp->bio2);
 		bio_pair_release(bp);
-		return 0;
+		return;
 	}
 
 	sector_offset = bio->bi_sector;
@@ -511,10 +508,9 @@ static int raid0_make_request(mddev_t *mddev, struct bio *bio)
 	bio->bi_bdev = tmp_dev->bdev;
 	bio->bi_sector = sector_offset + zone->dev_start +
 		tmp_dev->data_offset;
-	/*
-	 * Let the main block layer submit the IO and resolve recursion:
-	 */
-	return 1;
+
+	generic_make_request(bio);
+	return;
 
 bad_map:
 	printk("md/raid0:%s: make_request bug: can't convert block across chunks"
@@ -523,7 +519,7 @@ bad_map:
 	       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
 
 	bio_io_error(bio);
-	return 0;
+	return;
 }
 
 static void raid0_status(struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 32323f0afd89..97f2a5f977b1 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -785,7 +785,7 @@ do_sync_io:
 	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 }
 
-static int make_request(mddev_t *mddev, struct bio * bio)
+static void make_request(mddev_t *mddev, struct bio * bio)
 {
 	conf_t *conf = mddev->private;
 	mirror_info_t *mirror;
@@ -870,7 +870,7 @@ read_again:
 		if (rdisk < 0) {
 			/* couldn't find anywhere to read from */
 			raid_end_bio_io(r1_bio);
-			return 0;
+			return;
 		}
 		mirror = conf->mirrors + rdisk;
 
@@ -928,7 +928,7 @@ read_again:
 			goto read_again;
 		} else
 			generic_make_request(read_bio);
-		return 0;
+		return;
 	}
 
 	/*
@@ -1119,8 +1119,6 @@ read_again:
 
 	if (do_sync || !bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
-
-	return 0;
 }
 
 static void status(struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 8b29cd4f01c8..04b625e1cb60 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -825,7 +825,7 @@ static void unfreeze_array(conf_t *conf)
 	spin_unlock_irq(&conf->resync_lock);
 }
 
-static int make_request(mddev_t *mddev, struct bio * bio)
+static void make_request(mddev_t *mddev, struct bio * bio)
 {
 	conf_t *conf = mddev->private;
 	mirror_info_t *mirror;
@@ -844,7 +844,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
-		return 0;
+		return;
 	}
 
 	/* If this request crosses a chunk boundary, we need to
@@ -876,10 +876,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 		conf->nr_waiting++;
 		spin_unlock_irq(&conf->resync_lock);
 
-		if (make_request(mddev, &bp->bio1))
-			generic_make_request(&bp->bio1);
-		if (make_request(mddev, &bp->bio2))
-			generic_make_request(&bp->bio2);
+		make_request(mddev, &bp->bio1);
+		make_request(mddev, &bp->bio2);
 
 		spin_lock_irq(&conf->resync_lock);
 		conf->nr_waiting--;
@@ -887,14 +885,14 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 		spin_unlock_irq(&conf->resync_lock);
 
 		bio_pair_release(bp);
-		return 0;
+		return;
 	bad_map:
 		printk("md/raid10:%s: make_request bug: can't convert block across chunks"
 		       " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
 		       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
 
 		bio_io_error(bio);
-		return 0;
+		return;
 	}
 
 	md_write_start(mddev, bio);
@@ -937,7 +935,7 @@ read_again:
 		slot = r10_bio->read_slot;
 		if (disk < 0) {
 			raid_end_bio_io(r10_bio);
-			return 0;
+			return;
 		}
 		mirror = conf->mirrors + disk;
 
@@ -985,7 +983,7 @@ read_again:
 			goto read_again;
 		} else
 			generic_make_request(read_bio);
-		return 0;
+		return;
 	}
 
 	/*
@@ -1157,7 +1155,6 @@ retry_write:
 
 	if (do_sync || !mddev->bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
-	return 0;
 }
 
 static void status(struct seq_file *seq, mddev_t *mddev)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index dbae459fb02d..96b7f6a1b6f2 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3695,7 +3695,7 @@ static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf)
 	return sh;
 }
 
-static int make_request(mddev_t *mddev, struct bio * bi)
+static void make_request(mddev_t *mddev, struct bio * bi)
 {
 	raid5_conf_t *conf = mddev->private;
 	int dd_idx;
@@ -3708,7 +3708,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 
 	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bi);
-		return 0;
+		return;
 	}
 
 	md_write_start(mddev, bi);
@@ -3716,7 +3716,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 	if (rw == READ &&
 	     mddev->reshape_position == MaxSector &&
 	     chunk_aligned_read(mddev,bi))
-		return 0;
+		return;
 
 	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
 	last_sector = bi->bi_sector + (bi->bi_size>>9);
@@ -3851,8 +3851,6 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 
 		bio_endio(bi, 0);
 	}
-
-	return 0;
 }
 
 static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks);