debugfs: unproxify files created through debugfs_create_blob() (83b711cb) · Commits · 戴 / test

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:

Nicolai Stange <nicstange@gmail.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/debugfs/file.c

+10 −3

Original line number	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)
		{
		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);
		debugfs_use_file_finish(srcu_idx);
		return r;
		}

		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 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);

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