From: Linus Torvalds <[email protected]> commit 551d44200152cb26f75d2ef990aeb6185b7e37fd upstream.
The default_gfp() helper that I added is not wrong, but it turns out that it causes unnecessary headaches for 'sparse' which doesn't support the use of __VA_OPT__ (introduced in C++20 and C23, and supported by gcc and clang for a long time). We do already use __VA_OPT__ in some other cases in the kernel (drm/xe and btrfs), but it has been fairly limited. Now it triggers for pretty much everything, and sparse ends up not working at all. We can use the traditional gcc ',##__VA_ARGS__' syntax instead: it may not be the "C standard" way and is slightly less natural in this context, but it is the traditional model for this and avoids the sparse problem. Reported-and-tested-by: Ricardo Ribalda <[email protected]> Reported-and-tested-by: Richard Fitzgerald <[email protected]> Reported-by: Ben Dooks <[email protected]> Fixes: e19e1b480ac7 ("add default_gfp() helper macro and use it in the new *alloc_obj() helpers") Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Eric Biggers <[email protected]> --- include/linux/gfp.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index abe4282fbdb1..c7621a0714c1 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -13,8 +13,8 @@ struct vm_area_struct; struct mempolicy; /* Helper macro to avoid gfp flags if they are the default one */ -#define __default_gfp(a,...) a -#define default_gfp(...) __default_gfp(__VA_ARGS__ __VA_OPT__(,) GFP_KERNEL) +#define __default_gfp(a,b,...) b +#define default_gfp(...) __default_gfp(,##__VA_ARGS__,GFP_KERNEL) /* Convert GFP flags to their corresponding migrate type */ #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE) -- 2.55.0
