Re: [PATCH v2] ath11k: remove error checking for debugfs_create_file()

[Jeff Johnson <quic_jjohnson@quicinc.com>]

On 10/28/2024 8:41 PM, Julian Calaby wrote:
> The big question for me is this:
> 
>> Since the relayfs functionality that spectral scan uses is dependent upon
>> debugfs
> 
> Why?
> 
> This seems to go against the general guidance that debugfs should
> essentially be "fire and forget" and return values shouldn't be
> checked.
> 
> IMHO it comes down to one of two outcomes here:
> 
> 1. Spectral scan isn't necessary for normal operation so we shouldn't
> initialise that functionality if we can't use debugfs, which violates
> the "don't check return values" guidance
> 2. We should break that dependency
> 
> I can envisage a lot of people making the sensible assumption that a
> non-debug kernel doesn't need debugfs and therefore disabling it on
> their thing, but also it seems to be enabled everywhere I have access
> to: Debian Stable, WSL and Bazzite. So I could be completely missing
> the point here.

https://docs.kernel.org/filesystems/relay.html

The relay interface needs a struct dentry * and debugfs provides that.
And as a result userspace expects the relay file to be there as well.

/jeff