fs: remove mapping->backing_dev_info

Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

32 files changed, 8 insertions, 91 deletions

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index a24891b97547..6e29bf2db536 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -104,11 +104,9 @@ static int raw_release(struct inode *inode, struct file *filp)
 
         mutex_lock(&raw_mutex);
         bdev = raw_devices[minor].binding;
-        if (--raw_devices[minor].inuse == 0) {
+        if (--raw_devices[minor].inuse == 0)
                 /* Here  inode->i_mapping == bdev->bd_inode->i_mapping  */
                 inode->i_mapping = &inode->i_data;
-                inode->i_mapping->backing_dev_info = &default_backing_dev_info;
-        }
         mutex_unlock(&raw_mutex);
 
         blkdev_put(bdev, filp->f_mode | FMODE_EXCL);
diff --git a/fs/aio.c b/fs/aio.c
index 6f13d3fab07f..3bf8b1d250c3 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -176,7 +176,6 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 
         inode->i_mapping->a_ops = &aio_ctx_aops;
         inode->i_mapping->private_data = ctx;
-        inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
         inode->i_size = PAGE_SIZE * nr_pages;
 
         path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 026ca7b8431c..a9f92794d7a0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -60,19 +60,6 @@ static void bdev_write_inode(struct inode *inode)
         spin_unlock(&inode->i_lock);
 }
 
-/*
- * Move the inode from its current bdi to a new bdi.  Make sure the inode
- * is clean before moving so that it doesn't linger on the old bdi.
- */
-static void bdev_inode_switch_bdi(struct inode *inode,
-                        struct backing_dev_info *dst)
-{
-        spin_lock(&inode->i_lock);
-        WARN_ON_ONCE(inode->i_state & I_DIRTY);
-        inode->i_data.backing_dev_info = dst;
-        spin_unlock(&inode->i_lock);
-}
-
 /* Kill _all_ buffers and pagecache , dirty or not.. */
 void kill_bdev(struct block_device *bdev)
 {
@@ -589,7 +576,6 @@ struct block_device *bdget(dev_t dev)
                 inode->i_bdev = bdev;
                 inode->i_data.a_ops = &def_blk_aops;
                 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
-                inode->i_data.backing_dev_info = &default_backing_dev_info;
                 spin_lock(&bdev_lock);
                 list_add(&bdev->bd_list, &all_bdevs);
                 spin_unlock(&bdev_lock);
@@ -1150,8 +1136,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                 bdev->bd_queue = disk->queue;
                 bdev->bd_contains = bdev;
                 if (!partno) {
-                        struct backing_dev_info *bdi;
-
                         ret = -ENXIO;
                         bdev->bd_part = disk_get_part(disk, partno);
                         if (!bdev->bd_part)
@@ -1177,11 +1161,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                 }
                         }
 
-                        if (!ret) {
+                        if (!ret)
                                 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
-                                bdi = blk_get_backing_dev_info(bdev);
-                                bdev_inode_switch_bdi(bdev->bd_inode, bdi);
-                        }
 
                         /*
                          * If the device is invalidated, rescan partition
@@ -1208,8 +1189,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                         if (ret)
                                 goto out_clear;
                         bdev->bd_contains = whole;
-                        bdev_inode_switch_bdi(bdev->bd_inode,
-                                whole->bd_inode->i_data.backing_dev_info);
                         bdev->bd_part = disk_get_part(disk, partno);
                         if (!(disk->flags & GENHD_FL_UP) ||
                             !bdev->bd_part || !bdev->bd_part->nr_sects) {
@@ -1249,7 +1228,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
         bdev->bd_disk = NULL;
         bdev->bd_part = NULL;
         bdev->bd_queue = NULL;
-        bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info);
         if (bdev != bdev->bd_contains)
                 __blkdev_put(bdev->bd_contains, mode, 1);
         bdev->bd_contains = NULL;
@@ -1474,8 +1452,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                  * dirty data before.
                  */
                 bdev_write_inode(bdev->bd_inode);
-                bdev_inode_switch_bdi(bdev->bd_inode,
-                                        &default_backing_dev_info);
         }
         if (bdev->bd_contains == bdev) {
                 if (disk->fops->release)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index afc4092989cd..1ec872e3a926 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2318,7 +2318,6 @@ int open_ctree(struct super_block *sb,
          */
         fs_info->btree_inode->i_size = OFFSET_MAX;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
-        fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
 
         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8bf326affb94..54bcf639d1cf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3608,7 +3608,6 @@ cache_acl:
         switch (inode->i_mode & S_IFMT) {
         case S_IFREG:
                 inode->i_mapping->a_ops = &btrfs_aops;
-                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
                 inode->i_fop = &btrfs_file_operations;
                 inode->i_op = &btrfs_file_inode_operations;
@@ -3623,7 +3622,6 @@ cache_acl:
         case S_IFLNK:
                 inode->i_op = &btrfs_symlink_inode_operations;
                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
-                inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 break;
         default:
                 inode->i_op = &btrfs_special_inode_operations;
@@ -6088,7 +6086,6 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         inode->i_fop = &btrfs_file_operations;
         inode->i_op = &btrfs_file_inode_operations;
         inode->i_mapping->a_ops = &btrfs_aops;
-        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
 
         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
         if (err)
@@ -9203,7 +9200,6 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         inode->i_fop = &btrfs_file_operations;
         inode->i_op = &btrfs_file_inode_operations;
         inode->i_mapping->a_ops = &btrfs_aops;
-        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 
         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
@@ -9247,7 +9243,6 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 
         inode->i_op = &btrfs_symlink_inode_operations;
         inode->i_mapping->a_ops = &btrfs_symlink_aops;
-        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
         inode_set_bytes(inode, name_len);
         btrfs_i_size_write(inode, name_len);
         err = btrfs_update_inode(trans, root, inode);
@@ -9459,7 +9454,6 @@ static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
         inode->i_op = &btrfs_file_inode_operations;
 
         inode->i_mapping->a_ops = &btrfs_aops;
-        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 
         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index f61a74115beb..6b5173605154 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -783,8 +783,6 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
         }
 
         inode->i_mapping->a_ops = &ceph_aops;
-        inode->i_mapping->backing_dev_info =
-                &ceph_sb_to_client(inode->i_sb)->backing_dev_info;
 
         switch (inode->i_mode & S_IFMT) {
         case S_IFIFO:
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 0c3ce464cae4..2d4f37235ed0 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -937,8 +937,6 @@ retry_iget5_locked:
                         inode->i_flags |= S_NOATIME | S_NOCMTIME;
                 if (inode->i_state & I_NEW) {
                         inode->i_ino = hash;
-                        if (S_ISREG(inode->i_mode))
-                                inode->i_data.backing_dev_info = sb->s_bdi;
 #ifdef CONFIG_CIFS_FSCACHE
                         /* initialize per-inode cache cookie pointer */
                         CIFS_I(inode)->fscache = NULL;
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index 0ad6b4d6de00..65af86147154 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -131,7 +131,6 @@ struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
         if (inode) {
                 inode->i_ino = get_next_ino();
                 inode->i_mapping->a_ops = &configfs_aops;
-                inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
                 inode->i_op = &configfs_inode_operations;
 
                 if (sd->s_iattr) {
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 1686dc2da9fd..34b36a504059 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -67,7 +67,6 @@ static int ecryptfs_inode_set(struct inode *inode, void *opaque)
         inode->i_ino = lower_inode->i_ino;
         inode->i_version++;
         inode->i_mapping->a_ops = &ecryptfs_aops;
-        inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
 
         if (S_ISLNK(inode->i_mode))
                 inode->i_op = &ecryptfs_symlink_iops;
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index f1d3d4eb8c4f..6fc91df99ff8 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1214,7 +1214,6 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
                 memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));
         }
 
-        inode->i_mapping->backing_dev_info = sb->s_bdi;
         if (S_ISREG(inode->i_mode)) {
                 inode->i_op = &exofs_file_inode_operations;
                 inode->i_fop = &exofs_file_operations;
@@ -1314,7 +1313,6 @@ struct inode *exofs_new_inode(struct inode *dir, umode_t mode)
 
         set_obj_2bcreated(oi);
 
-        inode->i_mapping->backing_dev_info = sb->s_bdi;
         inode_init_owner(inode, dir, mode);
         inode->i_ino = sbi->s_nextid++;
         inode->i_blkbits = EXOFS_BLKSHIFT;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index f38256e4476e..e8799c11424b 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -308,7 +308,6 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
                         inode->i_flags |= S_NOCMTIME;
                 inode->i_generation = generation;
-                inode->i_data.backing_dev_info = &fc->bdi;
                 fuse_init_inode(inode, attr);
                 unlock_new_inode(inode);
         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index a23524aa3eac..08ea717981f7 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -775,7 +775,6 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
                 mapping->flags = 0;
                 mapping_set_gfp_mask(mapping, GFP_NOFS);
                 mapping->private_data = NULL;
-                mapping->backing_dev_info = s->s_bdi;
                 mapping->writeback_index = 0;
         }
 
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 8633ad328ee2..efc8e254787c 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -112,7 +112,6 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
         mapping->flags = 0;
         mapping_set_gfp_mask(mapping, GFP_NOFS);
         mapping->private_data = NULL;
-        mapping->backing_dev_info = sb->s_bdi;
         mapping->writeback_index = 0;
 
         spin_lock_init(&sdp->sd_log_lock);
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index de7c95c7d840..c274aca8e8dc 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -492,7 +492,6 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
                                 &hugetlbfs_i_mmap_rwsem_key);
                 inode->i_mapping->a_ops = &hugetlbfs_aops;
-                inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
                 inode->i_mapping->private_data = resv_map;
                 info = HUGETLBFS_I(inode);
diff --git a/fs/inode.c b/fs/inode.c
index aa149e7262ac..e4e8caa7464c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -170,20 +170,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
         atomic_set(&mapping->i_mmap_writable, 0);
         mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
         mapping->private_data = NULL;
-        mapping->backing_dev_info = &default_backing_dev_info;
         mapping->writeback_index = 0;
-
-        /*
-         * If the block_device provides a backing_dev_info for client
-         * inodes then use that.  Otherwise the inode share the bdev's
-         * backing_dev_info.
-         */
-        if (sb->s_bdev) {
-                struct backing_dev_info *bdi;
-
-                bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
-                mapping->backing_dev_info = bdi;
-        }
         inode->i_private = NULL;
         inode->i_mapping = mapping;
         INIT_HLIST_HEAD(&inode->i_dentry);      /* buggered by rcu freeing */
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 06f06887b2d2..9000874a945b 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -286,7 +286,6 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
         kernfs_get(kn);
         inode->i_private = kn;
         inode->i_mapping->a_ops = &kernfs_aops;
-        inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
         inode->i_op = &kernfs_iops;
 
         set_default_inode_attr(inode, kn->mode);
diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index a699a3fc62c0..01a9e16e9782 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -267,7 +267,6 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)
         if (inode) {
                 atomic_set(&NCP_FINFO(inode)->opened, info->opened);
 
-                inode->i_mapping->backing_dev_info = sb->s_bdi;
                 inode->i_ino = info->ino;
                 ncp_set_attr(inode, info);
                 if (S_ISREG(inode->i_mode)) {
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 4bffe637ea32..24aac72420f4 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -387,7 +387,6 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
                 if (S_ISREG(inode->i_mode)) {
                         inode->i_fop = NFS_SB(sb)->nfs_client->rpc_ops->file_ops;
                         inode->i_data.a_ops = &nfs_file_aops;
-                        inode->i_data.backing_dev_info = &NFS_SB(sb)->backing_dev_info;
                 } else if (S_ISDIR(inode->i_mode)) {
                         inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->dir_inode_ops;
                         inode->i_fop = &nfs_dir_operations;
diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index 57ceaf33d177..748ca238915a 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -172,7 +172,6 @@ int nilfs_init_gcinode(struct inode *inode)
         inode->i_mode = S_IFREG;
         mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
         inode->i_mapping->a_ops = &empty_aops;
-        inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
 
         ii->i_flags = 0;
         nilfs_bmap_init_gc(ii->i_bmap);
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index c4dcd1db57ee..892cf5ffdb8e 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -429,7 +429,6 @@ int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
 
         inode->i_mode = S_IFREG;
         mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
-        inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
 
         inode->i_op = &def_mdt_iops;
         inode->i_fop = &def_mdt_fops;
@@ -457,13 +456,12 @@ int nilfs_mdt_setup_shadow_map(struct inode *inode,
                                struct nilfs_shadow_map *shadow)
 {
         struct nilfs_mdt_info *mi = NILFS_MDT(inode);
-        struct backing_dev_info *bdi = inode->i_sb->s_bdi;
 
         INIT_LIST_HEAD(&shadow->frozen_buffers);
         address_space_init_once(&shadow->frozen_data);
-        nilfs_mapping_init(&shadow->frozen_data, inode, bdi);
+        nilfs_mapping_init(&shadow->frozen_data, inode);
         address_space_init_once(&shadow->frozen_btnodes);
-        nilfs_mapping_init(&shadow->frozen_btnodes, inode, bdi);
+        nilfs_mapping_init(&shadow->frozen_btnodes, inode);
         mi->mi_shadow = shadow;
         return 0;
 }
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index da276640f776..700ecbcca55d 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -461,14 +461,12 @@ unsigned nilfs_page_count_clean_buffers(struct page *page,
         return nc;
 }
 
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode,
-                        struct backing_dev_info *bdi)
+void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
 {
         mapping->host = inode;
         mapping->flags = 0;
         mapping_set_gfp_mask(mapping, GFP_NOFS);
         mapping->private_data = NULL;
-        mapping->backing_dev_info = bdi;
         mapping->a_ops = &empty_aops;
 }
 
diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h
index ef30c5c2426f..a43b8287d012 100644
--- a/fs/nilfs2/page.h
+++ b/fs/nilfs2/page.h
@@ -57,8 +57,7 @@ int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
 void nilfs_copy_back_pages(struct address_space *, struct address_space *);
 void nilfs_clear_dirty_page(struct page *, bool);
 void nilfs_clear_dirty_pages(struct address_space *, bool);
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode,
-                        struct backing_dev_info *bdi);
+void nilfs_mapping_init(struct address_space *mapping, struct inode *inode);
 unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned);
 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
                                             sector_t start_blk,
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 3d4bbac36bea..5bc2a1cf73c3 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -166,7 +166,7 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
         ii->i_state = 0;
         ii->i_cno = 0;
         ii->vfs_inode.i_version = 1;
-        nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode, sb->s_bdi);
+        nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
         return &ii->vfs_inode;
 }
 
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index 6000d3029b26..061ba6a91bf2 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -398,7 +398,6 @@ static struct inode *dlmfs_get_root_inode(struct super_block *sb)
         if (inode) {
                 inode->i_ino = get_next_ino();
                 inode_init_owner(inode, NULL, mode);
-                inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
                 inc_nlink(inode);
 
@@ -422,7 +421,6 @@ static struct inode *dlmfs_get_inode(struct inode *parent,
 
         inode->i_ino = get_next_ino();
         inode_init_owner(inode, parent, mode);
-        inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 
         ip = DLMFS_I(inode);
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index ad4d712002f4..889d558b4e05 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -59,7 +59,6 @@ struct inode *ramfs_get_inode(struct super_block *sb,
                 inode->i_ino = get_next_ino();
                 inode_init_owner(inode, dir, mode);
                 inode->i_mapping->a_ops = &ramfs_aops;
-                inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
                 mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
                 mapping_set_unevictable(inode->i_mapping);
                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index e98dd88197d5..268733cda397 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -355,9 +355,6 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
         case ROMFH_REG:
                 i->i_fop = &romfs_ro_fops;
                 i->i_data.a_ops = &romfs_aops;
-                if (i->i_sb->s_mtd)
-                        i->i_data.backing_dev_info =
-                                i->i_sb->s_mtd->backing_dev_info;
                 if (nextfh & ROMFH_EXEC)
                         mode |= S_IXUGO;
                 break;
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index ea41649e4ca5..c49b1981ac95 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -108,8 +108,6 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
         inode->i_mtime = inode->i_atime = inode->i_ctime =
                          ubifs_current_time(inode);
         inode->i_mapping->nrpages = 0;
-        /* Disable readahead */
-        inode->i_mapping->backing_dev_info = &c->bdi;
 
         switch (mode & S_IFMT) {
         case S_IFREG:
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index ed93dc6ae245..6197154f36ca 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -156,9 +156,6 @@ struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
         if (err)
                 goto out_invalid;
 
-        /* Disable read-ahead */
-        inode->i_mapping->backing_dev_info = &c->bdi;
-
         switch (inode->i_mode & S_IFMT) {
         case S_IFREG:
                 inode->i_mapping->a_ops = &ubifs_file_address_operations;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1dada399aa23..65d02de342e1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -34,6 +34,7 @@
 #include <asm/byteorder.h>
 #include <uapi/linux/fs.h>
 
+struct backing_dev_info;
 struct export_operations;
 struct hd_geometry;
 struct iovec;
@@ -394,7 +395,6 @@ int pagecache_write_end(struct file *, struct address_space *mapping,
                                 loff_t pos, unsigned len, unsigned copied,
                                 struct page *page, void *fsdata);
 
-struct backing_dev_info;
 struct address_space {
         struct inode            *host;          /* owner: inode, block_device */
         struct radix_tree_root  page_tree;      /* radix tree of all pages */
@@ -409,7 +409,6 @@ struct address_space {
         pgoff_t                 writeback_index;/* writeback starts here */
         const struct address_space_operations *a_ops;   /* methods */
         unsigned long           flags;          /* error bits/gfp mask */
-        struct backing_dev_info *backing_dev_info; /* device readahead, etc */
         spinlock_t              private_lock;   /* for use by the address_space */
         struct list_head        private_list;   /* ditto */
         void                    *private_data;  /* ditto */
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 16c68958aeda..52e0c7652448 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -24,7 +24,6 @@ struct backing_dev_info noop_backing_dev_info = {
         .name           = "noop",
         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
-EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
 static struct class *bdi_class;
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 1b77eaf589fd..4c61d3d5bfb4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1410,7 +1410,6 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
                 inode->i_ino = get_next_ino();
                 inode_init_owner(inode, dir, mode);
                 inode->i_blocks = 0;
-                inode->i_mapping->backing_dev_info = &noop_backing_dev_info;
                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
                 inode->i_generation = get_seconds();
                 info = SHMEM_I(inode);
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 1c137b69ecde..405923f77334 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -37,7 +37,6 @@ struct address_space swapper_spaces[MAX_SWAPFILES] = {
                 .page_tree      = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
                 .i_mmap_writable = ATOMIC_INIT(0),
                 .a_ops          = &swap_aops,
-                .backing_dev_info = &noop_backing_dev_info,
         }
 };