[PATCH 13/39] convert bpf

[Al Viro]

object creation goes through the normal VFS paths or approximation
thereof (user_path_create()/done_path_create() in case of bpf_obj_do_pin(),
open-coded simple_{start,done}_creating() in bpf_iter_link_pin_kernel()
at mount time), removals go entirely through the normal VFS paths (and
->unlink() is simple_unlink() there).

Enough to have bpf_dentry_finalize() use d_make_persistent() instead
of dget() and we are done.

Convert bpf_iter_link_pin_kernel() to simple_{start,done}_creating(),
while we are at it.

Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
---
 kernel/bpf/inode.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 5c2e96b19392..b9ef1f80ade5 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -144,8 +144,7 @@ static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
 static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode,
 				struct inode *dir)
 {
-	d_instantiate(dentry, inode);
-	dget(dentry);
+	d_make_persistent(dentry, inode);
 
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 }
@@ -420,16 +419,12 @@ static int bpf_iter_link_pin_kernel(struct dentry *parent,
 	struct dentry *dentry;
 	int ret;
 
-	inode_lock(parent->d_inode);
-	dentry = lookup_noperm(&QSTR(name), parent);
-	if (IS_ERR(dentry)) {
-		inode_unlock(parent->d_inode);
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
-	}
 	ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops,
 			    &bpf_iter_fops);
-	dput(dentry);
-	inode_unlock(parent->d_inode);
+	simple_done_creating(dentry);
 	return ret;
 }
 
@@ -1080,7 +1075,7 @@ static void bpf_kill_super(struct super_block *sb)
 {
 	struct bpf_mount_opts *opts = sb->s_fs_info;
 
-	kill_litter_super(sb);
+	kill_anon_super(sb);
 	kfree(opts);
 }
 
-- 
2.47.3