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

[Jeff Johnson]

On 10/28/2024 7:02 AM, Kalle Valo wrote:
> Zhen Lei <thunder.leizhen at huawei.com> writes:
> 
>> Driver ath11k can work fine even if the debugfs files fail to be created.
>> Therefore, the return value check of debugfs_create_file() should be
>> ignored, as it says.
>>
>> Suggested-by: Jeff Johnson <quic_jjohnson at quicinc.com>
>> Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
> 
> Are you just guessing or did you confirm on a real device that ath11k
> spectral really works without debugfs?

The debugfs_create_file() documentation tells us:
 * NOTE: it's expected that most callers should _ignore_ the errors returned
 * by this function. Other debugfs functions handle the fact that the "dentry"
 * passed to them could be an error and they don't crash in that case.
 * Drivers should generally work fine even if debugfs fails to init anyway.

The caveat is that any driver functionality that relies upon debugfs obviously
won't work if the underlying file isn't created. Hence the language that the
driver "should generally work fine" since all functionality that isn't tied to
debugfs will still be available.

Since the relayfs functionality that spectral scan uses is dependent upon
debugfs, this functionality won't work if the debugfs operation fails. So the
question is, if that fails, do you continue running the driver that generally
works fine supporting all other wifi operations, or do you return an error,
and as part of the error handling, not init the driver and hence have no wifi
operation?

The one thing I didn't check is that although the documentation tells us that
debugfs functions handle an "error" dentry, I didn't check if relayfs handles it.

/jeff