On Wed, Jan 12, 2022 at 10:26:08AM -0800, Suren Baghdasaryan wrote: > On Wed, Jan 12, 2022 at 10:16 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Wed, Jan 12, 2022 at 09:49:00AM -0800, Suren Baghdasaryan wrote: > > > > This happens with the following config: > > > > > > > > CONFIG_CGROUPS=n > > > > CONFIG_PSI=y > > > > > > > > With cgroups disabled these functions are defined as non-static but > > > > are not defined in the header > > > > (https://elixir.bootlin.com/linux/latest/source/include/linux/psi.h#L28) > > > > since the only external user cgroup.c is disabled. The cleanest way to > > > > fix these I think is by doing smth like this in psi.c: > > > > A cleaner way to solve these is simply: > > > > #ifndef CONFIG_CGROUPS > > static struct psi_trigger *psi_trigger_create(...); > > ... > > #endif > > > > I tested this works: > > > > $ cat foo5.c > > static int psi(void *); > > > > int psi(void *x) > > { > > return (int)(long)x; > > } > > > > int bar(void *x) > > { > > return psi(x); > > } > > $ gcc -W -Wall -O2 -c -o foo5.o foo5.c > > $ readelf -s foo5.o > > > > Symbol table '.symtab' contains 4 entries: > > Num: Value Size Type Bind Vis Ndx Name > > 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND > > 1: 0000000000000000 0 FILE LOCAL DEFAULT ABS foo5.c > > 2: 0000000000000000 0 SECTION LOCAL DEFAULT 1 .text > > 3: 0000000000000000 3 FUNC GLOBAL DEFAULT 1 bar > > > > Thanks Matthew! > That looks much cleaner. I'll post a separate patch to fix these. My > main concern was whether it's worth adding more code to satisfy this > warning but with this approach the code changes are minimal, so I'll > go ahead and post it shortly. Why not simply move the declarations of psi_trigger_create() and psi_trigger_destroy() in include/linux/psi.h outside of the '#ifdef CONFIG_CGROUPS' block, to match the .c file? They *could* be static when !CONFIG_CGROUPS, but IMO it's not worth bothering. - Eric
