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block: kill merge_bvec_fn() completely

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As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
 dm-era-target, and resolve merge conflicts]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Kent Overstreet
2015-04-27 23:48:34 -07:00
committed by Jens Axboe
parent 7140aafce2
commit 8ae126660f
32 changed files with 9 additions and 859 deletions
Download Patch File Download Diff File Expand all files Collapse all files

127
drivers/md/dm.c
View File

@@ -124,9 +124,8 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_MERGE_IS_OPTIONAL 6
#define DMF_DEFERRED_REMOVE 7
#define DMF_SUSPENDED_INTERNALLY 8
#define DMF_DEFERRED_REMOVE 6
#define DMF_SUSPENDED_INTERNALLY 7
/*
* A dummy definition to make RCU happy.
@@ -1725,67 +1724,6 @@ static void __split_and_process_bio(struct mapped_device *md,
* CRUD END
*---------------------------------------------------------------*/
static int dm_merge_bvec(struct request_queue *q,
struct bvec_merge_data *bvm,
struct bio_vec *biovec)
{
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_live_table_fast(md);
struct dm_target *ti;
sector_t max_sectors, max_size = 0;
if (unlikely(!map))
goto out;
ti = dm_table_find_target(map, bvm->bi_sector);
if (!dm_target_is_valid(ti))
goto out;
/*
* Find maximum amount of I/O that won't need splitting
*/
max_sectors = min(max_io_len(bvm->bi_sector, ti),
(sector_t) queue_max_sectors(q));
max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
/*
* FIXME: this stop-gap fix _must_ be cleaned up (by passing a sector_t
* to the targets' merge function since it holds sectors not bytes).
* Just doing this as an interim fix for stable@ because the more
* comprehensive cleanup of switching to sector_t will impact every
* DM target that implements a ->merge hook.
*/
if (max_size > INT_MAX)
max_size = INT_MAX;
/*
* merge_bvec_fn() returns number of bytes
* it can accept at this offset
* max is precomputed maximal io size
*/
if (max_size && ti->type->merge)
max_size = ti->type->merge(ti, bvm, biovec, (int) max_size);
/*
* If the target doesn't support merge method and some of the devices
* provided their merge_bvec method (we know this by looking for the
* max_hw_sectors that dm_set_device_limits may set), then we can't
* allow bios with multiple vector entries. So always set max_size
* to 0, and the code below allows just one page.
*/
else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
max_size = 0;
out:
dm_put_live_table_fast(md);
/*
* Always allow an entire first page
*/
if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
max_size = biovec->bv_len;
return max_size;
}
/*
* The request function that just remaps the bio built up by
* dm_merge_bvec.
@@ -2507,59 +2445,6 @@ static void __set_size(struct mapped_device *md, sector_t size)
i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
}
/*
* Return 1 if the queue has a compulsory merge_bvec_fn function.
*
* If this function returns 0, then the device is either a non-dm
* device without a merge_bvec_fn, or it is a dm device that is
* able to split any bios it receives that are too big.
*/
int dm_queue_merge_is_compulsory(struct request_queue *q)
{
struct mapped_device *dev_md;
if (!q->merge_bvec_fn)
return 0;
if (q->make_request_fn == dm_make_request) {
dev_md = q->queuedata;
if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
return 0;
}
return 1;
}
static int dm_device_merge_is_compulsory(struct dm_target *ti,
struct dm_dev *dev, sector_t start,
sector_t len, void *data)
{
struct block_device *bdev = dev->bdev;
struct request_queue *q = bdev_get_queue(bdev);
return dm_queue_merge_is_compulsory(q);
}
/*
* Return 1 if it is acceptable to ignore merge_bvec_fn based
* on the properties of the underlying devices.
*/
static int dm_table_merge_is_optional(struct dm_table *table)
{
unsigned i = 0;
struct dm_target *ti;
while (i < dm_table_get_num_targets(table)) {
ti = dm_table_get_target(table, i++);
if (ti->type->iterate_devices &&
ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
return 0;
}
return 1;
}
/*
* Returns old map, which caller must destroy.
*/
@@ -2569,7 +2454,6 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
int merge_is_optional;
size = dm_table_get_size(t);
@@ -2595,17 +2479,11 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
__bind_mempools(md, t);
merge_is_optional = dm_table_merge_is_optional(t);
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
dm_table_set_restrictions(t, q, limits);
if (merge_is_optional)
set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
else
clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
if (old_map)
dm_sync_table(md);
@@ -2886,7 +2764,6 @@ int dm_setup_md_queue(struct mapped_device *md)
case DM_TYPE_BIO_BASED:
dm_init_old_md_queue(md);
blk_queue_make_request(md->queue, dm_make_request);
blk_queue_merge_bvec(md->queue, dm_merge_bvec);
break;
}