fs: kill BDI_CAP_SWAP_BACKED
This bdi flag isn't too useful - we can determine that a vma is backed by
either swap or shmem trivially in the caller.
This also allows removing the backing_dev_info instaces for swap and shmem
in favor of noop_backing_dev_info.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/mm/shmem.c b/mm/shmem.c
index 73ba1df..1b77eaf 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -191,11 +191,6 @@
static const struct inode_operations shmem_special_inode_operations;
static const struct vm_operations_struct shmem_vm_ops;
-static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
- .ra_pages = 0, /* No readahead */
- .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
-};
-
static LIST_HEAD(shmem_swaplist);
static DEFINE_MUTEX(shmem_swaplist_mutex);
@@ -765,11 +760,11 @@
goto redirty;
/*
- * shmem_backing_dev_info's capabilities prevent regular writeback or
- * sync from ever calling shmem_writepage; but a stacking filesystem
- * might use ->writepage of its underlying filesystem, in which case
- * tmpfs should write out to swap only in response to memory pressure,
- * and not for the writeback threads or sync.
+ * Our capabilities prevent regular writeback or sync from ever calling
+ * shmem_writepage; but a stacking filesystem might use ->writepage of
+ * its underlying filesystem, in which case tmpfs should write out to
+ * swap only in response to memory pressure, and not for the writeback
+ * threads or sync.
*/
if (!wbc->for_reclaim) {
WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
@@ -1415,7 +1410,7 @@
inode->i_ino = get_next_ino();
inode_init_owner(inode, dir, mode);
inode->i_blocks = 0;
- inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
+ 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);
@@ -1461,7 +1456,7 @@
bool shmem_mapping(struct address_space *mapping)
{
- return mapping->backing_dev_info == &shmem_backing_dev_info;
+ return mapping->host->i_sb->s_op == &shmem_ops;
}
#ifdef CONFIG_TMPFS
@@ -3226,10 +3221,6 @@
if (shmem_inode_cachep)
return 0;
- error = bdi_init(&shmem_backing_dev_info);
- if (error)
- goto out4;
-
error = shmem_init_inodecache();
if (error)
goto out3;
@@ -3253,8 +3244,6 @@
out2:
shmem_destroy_inodecache();
out3:
- bdi_destroy(&shmem_backing_dev_info);
-out4:
shm_mnt = ERR_PTR(error);
return error;
}