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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240613161012.1dd2ff60@rorschach.local.home> On Thu, Jun 13, 2024 at 04:10:12PM -0400, Steven Rostedt wrote: > On Thu, 13 Jun 2024 13:04:20 -0700 > Andrew Morton wrote: > > > On Thu, 13 Jun 2024 15:34:02 -0400 Steven Rostedt wrote: > > > > > On Thu, 13 Jun 2024 22:22:18 +0300 > > > Alexey Dobriyan wrote: > > > > > > > g++ doesn't like forward enum declarations: > > > > > > > > error: use of enum ‘E’ without previous declaration > > > > 64 | enum E; > > > > > > But we don't care about g++. Do we? > > > > It appears that g++ is a useful enum declaration detector. > > > > I'm curious to know how even the above warning was generated. Does g++ > > work at all on Linux? With out-of-tree patch, yes. What happens is that "enum E;" works in C but doesn't work in C++. The fix (in C++) is to either delete, or change to "enum E:int;". The same applies to const struct S s; const struct S s = {}; First declaration is compile error in C++, sometimes it can be deleted. This patch is some "unused" parts merged together because it doesn't make sense to split this much -- every chunk is independent of each other. > > > I would make that a separate patch. > > > > What are you referring to here? > > The enum change should be separate from the struct changes. > > > > > > > > > > > Delete those which aren't used. > > > > > > > > Delete some unused/unnecessary forward struct declarations for a change. > > > > > > This is a clean up, but should have a better change log. Just something > > > simple like: > > > > > > Delete unnecessary forward struct declarations. > > > > Alexey specializes in cute changelogs. > > eh Steven is right. That's what my literature teacher said in high school. > > I do have a concern about the patch: has it been tested with all > > possible Kconfigs? No. There may be some configs in which the forward > > declaration is required. > > > > And... I'm a bit surprised that forward declarations are allowed in C. > > A billion years ago I used a C compiler which would use 16 bits for > > an enum if the enumted values would fit in 16 bits. And it would use 32 > > bits otherwise. So the enumerated values were *required* for the > > compiler to be able to figure out the sizeof. But it was a billion > > years ago. > > Well, I only looked at the one change in ftrace.h which has a > "struct seq_file;" that is not used anywhere else in the file, so that > one definitely can go. It was tested on arm64 allmodconfig too. OK if this is concern, I could dust off my compile test farm.