new wrapper: alloc_file_pseudo()

takes inode, vfsmount, name, O_... flags and file_operations and
either returns a new struct file (in which case inode reference we
held is consumed) or returns ERR_PTR(), in which case no refcounts
are altered.

converted aio_private_file() and sock_alloc_file() to it

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 16 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 9eea53887d6c..c3a8bac16374 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -215,9 +215,7 @@ static const struct address_space_operations aio_ctx_aops;
 
 static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 {
-        struct qstr this = QSTR_INIT("[aio]", 5);
         struct file *file;
-        struct path path;
         struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
         if (IS_ERR(inode))
                 return ERR_CAST(inode);
@@ -226,27 +224,17 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
         inode->i_mapping->private_data = ctx;
         inode->i_size = PAGE_SIZE * nr_pages;
 
-        path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
-        if (!path.dentry) {
-                iput(inode);
-                return ERR_PTR(-ENOMEM);
-        }
-        path.mnt = mntget(aio_mnt);
-
-        d_instantiate(path.dentry, inode);
-        file = alloc_file(&path, O_RDWR, &aio_ring_fops);
+        file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
+                                O_RDWR, &aio_ring_fops);
         if (IS_ERR(file))
-                path_put(&path);
+                iput(inode);
         return file;
 }
 
 static struct dentry *aio_mount(struct file_system_type *fs_type,
                                 int flags, const char *dev_name, void *data)
 {
-        static const struct dentry_operations ops = {
-                .d_dname        = simple_dname,
-        };
-        struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, &ops,
+        struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, NULL,
                                            AIO_RING_MAGIC);
 
         if (!IS_ERR(root))