On Thu, 2019-07-18 at 16:29 -0700, David Miller wrote: > From: Qian Cai <c...@lca.pw> > Date: Thu, 18 Jul 2019 19:26:47 -0400 > > > > > > >> On Jul 18, 2019, at 5:21 PM, Bill Wendling <mo...@google.com> wrote: > >> > >> [My previous response was marked as spam...] > >> > >> Top-of-tree clang says that it's const: > >> > >> $ gcc a.c -O2 && ./a.out > >> a is a const. > >> > >> $ clang a.c -O2 && ./a.out > >> a is a const. > > > > > > I used clang-7.0.1. So, this is getting worse where both GCC and clang will > start to suffer the > > same problem. > > Then rewrite the module parameter macros such that the non-constness > is evident to all compilers regardless of version. > > That is the place to fix this, otherwise we will just be adding hacks > all over the place rather than in just one spot.
The problem is that when the compiler is compiling be_main.o, it has no knowledge about what is going to happen in load_module(). The compiler can only see that a "const struct kernel_param_ops" "__param_ops_rx_frag_size" at the time with __param_ops_rx_frag_size.arg = &rx_frag_size but only in load_module()->parse_args()->parse_one()->param_set_ushort(), it changes "__param_ops_rx_frag_size.arg" which in-turn changes the value of "rx_frag_size".
