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Commit 83b711cb authored by Nicolai Stange's avatar Nicolai Stange Committed by Greg Kroah-Hartman
Browse files

debugfs: unproxify files created through debugfs_create_blob() 



Currently, the struct file_operations fops_blob associated with files
created through the debugfs_create_blob() helpers are not file
lifetime aware.

Thus, a lifetime managing proxy is created around fops_blob each time such
a file is opened which is an unnecessary waste of resources.

Implement file lifetime management for the fops_bool file_operations.
Namely, make read_file_blob() safe gainst file removals by means of
debugfs_use_file_start() and debugfs_use_file_finish().

Make debugfs_create_blob() create its files in non-proxying operation mode
by means of debugfs_create_file_unsafe().

Signed-off-by: default avatarNicolai Stange <nicstange@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4d45f797

fs/debugfs/file.c

+10 −3
Original line number Original line Diff line number Diff line
@@ -842,8 +842,15 @@ static ssize_t read_file_blob(struct file *file, char __user *user_buf, 
			      size_t count, loff_t *ppos)

			      size_t count, loff_t *ppos)

{

{

	struct debugfs_blob_wrapper *blob = file->private_data;

	struct debugfs_blob_wrapper *blob = file->private_data;

	return simple_read_from_buffer(user_buf, count, ppos, blob->data,

	ssize_t r;

	int srcu_idx;



	r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);

	if (likely(!r))

		r = simple_read_from_buffer(user_buf, count, ppos, blob->data,

					blob->size);

					blob->size);

	debugfs_use_file_finish(srcu_idx);

	return r;

}

}





static const struct file_operations fops_blob = {

static const struct file_operations fops_blob = {
@@ -880,7 +887,7 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode, 
				   struct dentry *parent,

				   struct dentry *parent,

				   struct debugfs_blob_wrapper *blob)

				   struct debugfs_blob_wrapper *blob)

{

{

	return debugfs_create_file(name, mode, parent, blob, &fops_blob);

	return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);

}

}

EXPORT_SYMBOL_GPL(debugfs_create_blob);

EXPORT_SYMBOL_GPL(debugfs_create_blob);