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, 27 insertions, 0 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 9b70ed2bbc4e..6b3723909342 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -184,6 +184,33 @@ struct file *alloc_file(const struct path *path, int flags,
 }
 EXPORT_SYMBOL(alloc_file);
 
+struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
+                                const char *name, int flags,
+                                const struct file_operations *fops)
+{
+        static const struct dentry_operations anon_ops = {
+                .d_dname = simple_dname
+        };
+        struct qstr this = QSTR_INIT(name, strlen(name));
+        struct path path;
+        struct file *file;
+
+        path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this);
+        if (!path.dentry)
+                return ERR_PTR(-ENOMEM);
+        if (!mnt->mnt_sb->s_d_op)
+                d_set_d_op(path.dentry, &anon_ops);
+        path.mnt = mntget(mnt);
+        d_instantiate(path.dentry, inode);
+        file = alloc_file(&path, flags, fops);
+        if (IS_ERR(file)) {
+                ihold(inode);
+                path_put(&path);
+        }
+        return file;
+}
+EXPORT_SYMBOL(alloc_file_pseudo);
+
 /* the real guts of fput() - releasing the last reference to file
  */
 static void __fput(struct file *file)