Tony Chuang <yhchuang@xxxxxxxxxxx> writes: >> From: Brian Norris [mailto:briannorris@xxxxxxxxxxxx] >> >> > +static inline void >> > +rtw_write32s_mask(struct rtw_dev *rtwdev, u32 addr, u32 mask, u32 data) >> > +{ >> > + BUILD_BUG_ON(addr < 0xC00 || addr >= 0xD00); >> >> This seems to be a non-traditional use of BUILD_BUG_ON(). Normally, I >> see this used for stuff that's guaranteed to be known at compile time -- >> structure offsets, constants, etc. This is usually (always?) a constant, >> but it passes through a function parameter, so I'm not sure if that's >> really guaranteed. >> >> Anyway...this is failing confusingly for me when I try to build: >> >> drivers/net/wireless/realtek/rtw88/rtw8822b.c: In function >> ‘rtw_write32s_mask’: >> drivers/net/wireless/realtek/rtw88/rtw8822b.c:230:176: error: call to >> ‘__compiletime_assert_230’ declared with attribute error: BUILD_BUG_ON >> failed: addr < 0xC00 || addr >= 0xD00 >> BUILD_BUG_ON(addr < 0xC00 || addr >= 0xD00); >> >> ^ >> >> I tried to pinpoint which call yielded this, and I think once I deleted >> enough calls to rtw_write32s_mask() it came down to this one: >> >> rtw_write32s_mask(rtwdev, REG_RFEINV, BIT(11) | BIT(10) | 0x3f, >> 0x0); >> >> which doesn't really make sense, as that's a value of 0xcbc. >> >> What I really think it comes down to is that you can't guarantee >> rtw_write32s_mask() will get inlined, and so BUILD_BUG_ON() may not know >> what to do with it. > > Yeah, you're right. I think we should turn it into macro. Does this really need to be a build time check? Like Brian said, this is not really common use of BUILD_BUG_ON(). I would just change it to WARN_ON_ONCE() or a ratelimited warning message so that we don't to have an ugly macro. -- Kalle Valo
