On 13.08.2021 08:54, Wei Chen wrote: >> From: Jan Beulich <[email protected]> >> Sent: 2021年8月11日 18:54 >> >> On 11.08.2021 12:23, Wei Chen wrote: >>> --- a/xen/arch/arm/platform.c >>> +++ b/xen/arch/arm/platform.c >>> @@ -27,6 +27,7 @@ extern const struct platform_desc _splatform[], >> _eplatform[]; >>> /* Pointer to the current platform description */ >>> static const struct platform_desc *platform; >>> >>> +extern unsigned int dma_bitsize; >> >> This is a no-go: Declarations need to live in a header which the producer >> and all consumers include. Else ... > > Ok, I will place it to a header. > >> >>> --- a/xen/common/page_alloc.c >>> +++ b/xen/common/page_alloc.c >>> @@ -227,7 +227,7 @@ static bool __read_mostly scrub_debug; >>> * Bit width of the DMA heap -- used to override NUMA-node-first. >>> * allocation strategy, which can otherwise exhaust low memory. >>> */ >>> -static unsigned int dma_bitsize; >>> +unsigned int dma_bitsize; >> >> ... a change here (of e.g. the type) will go unnoticed by the compiler, >> and the consumer of the variable may no longer work correctly. >> > > Sorry, I am not very clear about this comment.
I've merely been trying to explain _why_ the declaration needs to be in a header. Jan
