Re: [PATCH 3/3] selftests/efivarfs: Add create-read test

[Lingzhu Xiang <lxiang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 01/27/2013 06:47 AM, Jeremy Kerr wrote:
> +	if (!(rc < 0 && errno == EIO)) {
> +		fprintf(stderr, "Reading a new var should return -EIO\n");

What does the -EIO imply for reading a known empty file?

The file is empty. There is nothing to be read. No IO should actually 
happens.
The variable doesn't exist in nvram. What is the error? This won't make 
sense
for userspace.

Empty variable never exists in nvram per spec. Userspace doesn't need an 
extra
EIO to figure out this known fact. In the meantime, user would wonder if
something else has gone wrong? Returning zero for reading an empty file can
reserve EIO for something more informational.

Maybe at this time we just leave it as it is for other reasons. But at least
I don't think it's a good idea to mandate this behavior.