Re: [PATCH] proc: smoke test lseek()

[Matthew Wilcox]

On Wed, Apr 07, 2021 at 10:55:14PM +0300, Alexey Dobriyan wrote:
> Now that ->proc_lseek has been made mandatory it would be nice to test
> that nothing has been forgotten.

> @@ -45,6 +45,8 @@ static void f_reg(DIR *d, const char *filename)
>  	fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
>  	if (fd == -1)
>  		return;
> +	/* struct proc_ops::proc_lseek is mandatory if file is seekable. */
> +	(void)lseek(fd, 0, SEEK_SET);
>  	rv = read(fd, buf, sizeof(buf));
>  	assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
>  	close(fd);

why throw away the return value?  if it returns an error seeking to
offset 0, something is terribly wrong.