RE: Linux 4.4.256

[David Laight]

From: Willy Tarreau
> Sent: 06 February 2021 13:23
> 
> On Sat, Feb 06, 2021 at 02:11:13PM +0100, Willy Tarreau wrote:
> > Something like this looks more robust to me, it will use SUBLEVEL for
> > values 0 to 255 and 255 for any larger value:
> 
> diff --git a/Makefile b/Makefile
> index 7d86ad6ad36c..9b91b8815b40 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1252,7 +1252,7 @@ endef
> 
>  define filechk_version.h
>  	echo \#define LINUX_VERSION_CODE $(shell                         \
> -	expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \
> +	expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 255 \* \( 0$(SUBLEVEL) \> 255 \) +
> 0$(SUBLEVEL) \* \( 0$(SUBLEVEL) \<= 255 \) ); \
>  	echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))'
>  endef

Why not:
	$(shell echo $$(($(VERSION)<<16 + $(PATCHLEVEL)<<8 + ($(SUBVERSION) < 255 ? $(SUBVERSION) : 255))))
Untested, but I think only the one $ needs any kind of escape.
The extra leading zeros do have to go - $((...)) does octal :-(

	David

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