[PATCH 05/14] fs: don't allow kernel reads and writes without iter ops

[Al Viro]

On Thu, Oct 01, 2020 at 03:38:52PM -0700, Eric Biggers wrote:

>  	mutex_lock(&sbi->pipe_mutex);
>  	while (bytes) {
> -		wr = __kernel_write(file, data, bytes, NULL);
> +		wr = __kernel_write(file, data, bytes, &file->f_pos);

Better
	loff_t dummy = 0;
...
		wr = __kernel_write(file, data, bytes, &dummy);