On Tue, Mar 01, 2022 at 06:40:04PM +0100, Jakob Koschel wrote: > > > > On 1. Mar 2022, at 18:36, Greg KH <greg@xxxxxxxxx> wrote: > > > > On Tue, Mar 01, 2022 at 12:28:15PM +0100, Jakob Koschel wrote: > >> > >> > >>> On 1. Mar 2022, at 01:41, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >>> > >>> On Mon, Feb 28, 2022 at 1:47 PM Jakob Koschel <jakobkoschel@xxxxxxxxx> wrote: > >>>> > >>>> The goal of this is to get compiler warnings right? This would indeed be great. > >>> > >>> Yes, so I don't mind having a one-time patch that has been gathered > >>> using some automated checker tool, but I don't think that works from a > >>> long-term maintenance perspective. > >>> > >>> So if we have the basic rule being "don't use the loop iterator after > >>> the loop has finished, because it can cause all kinds of subtle > >>> issues", then in _addition_ to fixing the existing code paths that > >>> have this issue, I really would want to (a) get a compiler warning for > >>> future cases and (b) make it not actually _work_ for future cases. > >>> > >>> Because otherwise it will just happen again. > >>> > >>>> Changing the list_for_each_entry() macro first will break all of those cases > >>>> (e.g. the ones using 'list_entry_is_head()). > >>> > >>> So I have no problems with breaking cases that we basically already > >>> have a patch for due to your automated tool. There were certainly > >>> more than a handful, but it didn't look _too_ bad to just make the > >>> rule be "don't use the iterator after the loop". > >>> > >>> Of course, that's just based on that patch of yours. Maybe there are a > >>> ton of other cases that your patch didn't change, because they didn't > >>> match your trigger case, so I may just be overly optimistic here. > >> > >> Based on the coccinelle script there are ~480 cases that need fixing > >> in total. I'll now finish all of them and then split them by > >> submodules as Greg suggested and repost a patch set per submodule. > >> Sounds good? > > > > Sounds good to me! > > > > If you need help carving these up and maintaining them over time as > > different subsystem maintainers accept/ignore them, just let me know. > > Doing large patchsets like this can be tough without a lot of > > experience. > > Very much appreciated! > > There will probably be some cases that do not match one of the pattern > we already discussed and need separate attention. > > I was planning to start with one subsystem and adjust the coming ones > according to the feedback gather there instead of posting all of them > in one go. That seems wise. Feel free to use USB as a testing ground for this if you want to :) thanks, greg k-h
