[PATCH v4 50/54] convert rust_binderfs

Al Viro
2025-11-18T05:20:23Z

Parallel to binderfs stuff:
* use simple_start_creating()/simple_done_creating()/d_make_persistent()
instead of manual inode_lock()/lookup_noperm()/d_instanitate()/inode_unlock().
* allocate inode first - simpler cleanup that way.
* use simple_recursive_removal() instead of open-coding it.
* switch to kill_anon_super()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
drivers/android/binder/rust_binderfs.c | 121 +++++++------------------
1 file changed, 33 insertions(+), 88 deletions(-)

diff --git a/drivers/android/binder/rust_binderfs.c b/drivers/android/binder/rust_binderfs.c
index 6b497146b698..c69026df775c 100644
--- a/drivers/android/binder/rust_binderfs.c
+++ b/drivers/android/binder/rust_binderfs.c
@@ -178,28 +178,17 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
}

root = sb->s_root;
- inode_lock(d_inode(root));
-
- /* look it up */
- dentry = lookup_noperm(&QSTR(req->name), root);
+ dentry = simple_start_creating(root, req->name);
if (IS_ERR(dentry)) {
- inode_unlock(d_inode(root));
ret = PTR_ERR(dentry);
goto err;
}

- if (d_really_is_positive(dentry)) {
- /* already exists */
- dput(dentry);
- inode_unlock(d_inode(root));
- ret = -EEXIST;
- goto err;
- }
-
inode->i_private = device;
- d_instantiate(dentry, inode);
+ d_make_persistent(dentry, inode);
+
fsnotify_create(root->d_inode, dentry);
- inode_unlock(d_inode(root));
+ simple_done_creating(dentry);

return 0;

@@ -472,37 +461,9 @@ static struct inode *binderfs_make_inode(struct super_block *sb, int mode)
return ret;
}

-static struct dentry *binderfs_create_dentry(struct dentry *parent,
- const char *name)
-{
- struct dentry *dentry;
-
- dentry = lookup_noperm(&QSTR(name), parent);
- if (IS_ERR(dentry))
- return dentry;
-
- /* Return error if the file/dir already exists. */
- if (d_really_is_positive(dentry)) {
- dput(dentry);
- return ERR_PTR(-EEXIST);
- }
-
- return dentry;
-}
-
void rust_binderfs_remove_file(struct dentry *dentry)
{
- struct inode *parent_inode;
-
- parent_inode = d_inode(dentry->d_parent);
- inode_lock(parent_inode);
- if (simple_positive(dentry)) {
- dget(dentry);
- simple_unlink(parent_inode, dentry);
- d_delete(dentry);
- dput(dentry);
- }
- inode_unlock(parent_inode);
+ simple_recursive_removal(dentry, NULL);
}

static struct dentry *rust_binderfs_create_file(struct dentry *parent, const char *name,
@@ -510,31 +471,23 @@ static struct dentry *rust_binderfs_create_file(struct dentry *parent, const cha
void *data)
{
struct dentry *dentry;
- struct inode *new_inode, *parent_inode;
- struct super_block *sb;
-
- parent_inode = d_inode(parent);
- inode_lock(parent_inode);
-
- dentry = binderfs_create_dentry(parent, name);
- if (IS_ERR(dentry))
- goto out;
-
- sb = parent_inode->i_sb;
- new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
- if (!new_inode) {
- dput(dentry);
- dentry = ERR_PTR(-ENOMEM);
- goto out;
- }
+ struct inode *new_inode;

+ new_inode = binderfs_make_inode(parent->d_sb, S_IFREG | 0444);
+ if (!new_inode)
+ return ERR_PTR(-ENOMEM);
new_inode->i_fop = fops;
new_inode->i_private = data;
- d_instantiate(dentry, new_inode);
- fsnotify_create(parent_inode, dentry);

-out:
- inode_unlock(parent_inode);
+ dentry = simple_start_creating(parent, name);
+ if (IS_ERR(dentry)) {
+ iput(new_inode);
+ return dentry;
+ }
+
+ d_make_persistent(dentry, new_inode);
+ fsnotify_create(parent->d_inode, dentry);
+ simple_done_creating(dentry);
return dentry;
}

@@ -556,34 +509,26 @@ static struct dentry *binderfs_create_dir(struct dentry *parent,
const char *name)
{
struct dentry *dentry;
- struct inode *new_inode, *parent_inode;
- struct super_block *sb;
-
- parent_inode = d_inode(parent);
- inode_lock(parent_inode);
-
- dentry = binderfs_create_dentry(parent, name);
- if (IS_ERR(dentry))
- goto out;
+ struct inode *new_inode;

- sb = parent_inode->i_sb;
- new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
- if (!new_inode) {
- dput(dentry);
- dentry = ERR_PTR(-ENOMEM);
- goto out;
- }
+ new_inode = binderfs_make_inode(parent->d_sb, S_IFDIR | 0755);
+ if (!new_inode)
+ return ERR_PTR(-ENOMEM);

new_inode->i_fop = &simple_dir_operations;
new_inode->i_op = &simple_dir_inode_operations;

- set_nlink(new_inode, 2);
- d_instantiate(dentry, new_inode);
- inc_nlink(parent_inode);
- fsnotify_mkdir(parent_inode, dentry);
+ dentry = simple_start_creating(parent, name);
+ if (IS_ERR(dentry)) {
+ iput(new_inode);
+ return dentry;
+ }

-out:
- inode_unlock(parent_inode);
+ inc_nlink(parent->d_inode);
+ set_nlink(new_inode, 2);
+ d_make_persistent(dentry, new_inode);
+ fsnotify_mkdir(parent->d_inode, dentry);
+ simple_done_creating(dentry);
return dentry;
}

@@ -802,7 +747,7 @@ static void binderfs_kill_super(struct super_block *sb)
* During inode eviction struct binderfs_info is needed.
* So first wipe the super_block then free struct binderfs_info.
*/
- kill_litter_super(sb);
+ kill_anon_super(sb);

if (info && info->ipc_ns)
put_ipc_ns(info->ipc_ns);
--
2.47.3