On 21/08/2025 08:28, Muhammad Usama Anjum wrote:
As to -Wunused-parameter I am frankly not convinced it's worth the hassle. We're getting 90 lines changed in patch 6-8 just to mark parameters as unused, in other words noise to keep the compiler happy. It is not enabled by default in the kernel proper precisely because it is so noisy when callbacks are involved.
Patch 5 is clearly an improvement, but I'd rather take it without actually enabling -Wunused-parameter. The rest of this patch isn't that useful either IMHO.
Patch 5 removes genuinely unused parameters flagged by the compiler. If we drop the -Wunused-parameter option, however, new unused parameters will continue to creep in with future patches. The goal of enabling this warning is to surface such issues early so developers can address them during development, rather than later during review or debugging.
Long term, I’d like us to rely more on compiler and static analysis just like kernel to catch these kinds of problems proactively, instead of waiting until they’re reported or someone fixes them later. While it may feel like noise initially, this is largely a one-time cleanup—once done, developers will simply fix warnings as they arise, keeping the codebase cleaner going forward.
Agreed on the general principle, but I think the hassle is just too big for what we're getting in return here (see also Andrew's reply). New code may also introduce a bunch of unused parameters for legitimate reasons and it's easy to imagine contributors ignoring such seemingly harmless/irrelevant warnings instead of sprinkling __unused all over. My feeling is that unused parameters are expected to be allowed in the kernel and it isn't helpful to go against that expectation in just a small subset of kselftests.
- Kevin