};
/**
- * anon_inode_getfd - creates a new file instance by hooking it up to and
+ * anon_inode_getfd - creates a new file instance by hooking it up to an
* anonymous inode, and a dentry that describe the "class"
* of the file
*
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
- * All the files created with anon_inode_getfd() will share a single inode, by
+ * All the files created with anon_inode_getfd() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
* setup.
*/
{
struct qstr this;
struct dentry *dentry;
- struct inode *inode;
struct file *file;
int error, fd;
if (IS_ERR(anon_inode_inode))
return -ENODEV;
- file = get_empty_filp();
- if (!file)
- return -ENFILE;
-
- inode = igrab(anon_inode_inode);
- if (IS_ERR(inode)) {
- error = PTR_ERR(inode);
- goto err_put_filp;
- }
error = get_unused_fd();
if (error < 0)
- goto err_iput;
+ return error;
fd = error;
/*
dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this);
if (!dentry)
goto err_put_unused_fd;
+
+ /*
+ * We know the anon_inode inode count is always greater than zero,
+ * so we can avoid doing an igrab() and we can use an open-coded
+ * atomic_inc().
+ */
+ atomic_inc(&anon_inode_inode->i_count);
+
dentry->d_op = &anon_inodefs_dentry_operations;
/* Do not publish this dentry inside the global dentry hash table */
dentry->d_flags &= ~DCACHE_UNHASHED;
- d_instantiate(dentry, inode);
+ d_instantiate(dentry, anon_inode_inode);
- file->f_path.mnt = mntget(anon_inode_mnt);
- file->f_path.dentry = dentry;
- file->f_mapping = inode->i_mapping;
+ error = -ENFILE;
+ file = alloc_file(anon_inode_mnt, dentry,
+ FMODE_READ | FMODE_WRITE, fops);
+ if (!file)
+ goto err_dput;
+ file->f_mapping = anon_inode_inode->i_mapping;
file->f_pos = 0;
file->f_flags = O_RDWR;
- file->f_op = fops;
- file->f_mode = FMODE_READ | FMODE_WRITE;
file->f_version = 0;
file->private_data = priv;
fd_install(fd, file);
*pfd = fd;
- *pinode = inode;
+ *pinode = anon_inode_inode;
*pfile = file;
return 0;
+err_dput:
+ dput(dentry);
err_put_unused_fd:
put_unused_fd(fd);
-err_iput:
- iput(inode);
-err_put_filp:
- put_filp(file);
return error;
}
+EXPORT_SYMBOL_GPL(anon_inode_getfd);
/*
- * A single inode exist for all anon_inode files. Contrary to pipes,
- * anon_inode inodes has no per-instance data associated, so we can avoid
- * the allocation of multiple of them.
+ * A single inode exists for all anon_inode files. Contrary to pipes,
+ * anon_inode inodes have no associated per-instance data, so we need
+ * only allocate one of them.
*/
static struct inode *anon_inode_mkinode(void)
{