[PATCH] eal/unix: lower log level for reading files

[Morten Brørup]

> From: David Marchand [mailto:david.marchand at redhat.com]
> Sent: Friday, 27 October 2023 10.01
> 
> The eal_parse_sysfs_value helper both returns an error code and logs an
> error level message when something goes wrong.
> On the other hand, internal users of this helper either ignore this
> error code (like when trying to find out some numa information from the
> Linux sysfs, or discovering some optional feature), or add their own
> error
> logging when reading the file actually matters.
> 
> Lower this helper log messages to debug level as it provides no useful
> information to final DPDK users.

Such assumptions seem risky.

Please add __attribute__ ((warn_unused_result)) to this function's header, to support the assumption.

Alternatively, add a "bool may_not_exist" parameter to the function to choose the relevant log level.