Messages in this thread | | | Subject | Re: [PATCH v2 03/24] virtio: allow __virtioXX, __leXX in config space | From | Jason Wang <> | Date | Fri, 7 Aug 2020 11:26:55 +0800 |
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On 2020/8/6 下午1:58, Michael S. Tsirkin wrote: > On Thu, Aug 06, 2020 at 11:37:38AM +0800, Jason Wang wrote: >> On 2020/8/5 下午7:45, Michael S. Tsirkin wrote: >>>>> #define virtio_cread(vdev, structname, member, ptr) \ >>>>> do { \ >>>>> might_sleep(); \ >>>>> /* Must match the member's type, and be integer */ \ >>>>> - if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ >>>>> + if (!__virtio_typecheck(structname, member, *(ptr))) \ >>>>> (*ptr) = 1; \ >>>> A silly question, compare to using set()/get() directly, what's the value >>>> of the accessors macro here? >>>> >>>> Thanks >>> get/set don't convert to the native endian, I guess that's why >>> drivers use cread/cwrite. It is also nice that there's type >>> safety, checking the correct integer width is used. >> >> Yes, but this is simply because a macro is used here, how about just doing >> things similar like virtio_cread_bytes(): >> >> static inline void virtio_cread(struct virtio_device *vdev, >> unsigned int offset, >> void *buf, size_t len) >> >> >> And do the endian conversion inside? >> >> Thanks >> > Then you lose type safety. It's very easy to have an le32 field > and try to read it into a u16 by mistake. > > These macros are all about preventing bugs: and the whole patchset > is about several bugs sparse found - that is what prompted me to make > type checks more strict.
Yes, but we need to do the macro with compiler extensions. I wonder whether or not the kernel has already had something since this request here is pretty common?
Thanks
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