> MAX_PHYSMEM_BITS is a definition for sparsemem, and is only visible > when sparsemem is enabled. When sparsemem is disabled, asm/sparsemem.h > is not included (and should not be included) which means there is no > MAX_PHYSMEM_BITS definition. Missed that part :\, tks. > I don't think zsmalloc.c should be (ab)using MAX_PHYSMEM_BITS, and > your description above makes it sound like you expect it to always be > defined. > > If we want to have a definition for this, we shouldn't be playing > fragile games like: > > #ifndef MAX_POSSIBLE_PHYSMEM_BITS > #ifdef MAX_PHYSMEM_BITS > #define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS > #else > /* > * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just > * be PAGE_SHIFT > */ > #define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG > #endif > #endif > > but instead insist that MAX_PHYSMEM_BITS is defined _everywhere_. Is it okay to propose using only MAX_PHYSMEM_BITS for zsmalloc (like it was before commit 02390b87) instead, and make sure *at least* ARM 32/64 and x86/x64, for now, have it defined outside sparsemem headers as well ? This way I can WARN_ONCE(), instead of BUG(), when specific arch does not define it - enforcing behavior - showing BITS_PER_LONG is being used instead of MAX_PHYSMEM_BITS (warning, at least once, for the possibility of an overflow, like the issue showed in here).
