Re: [PATCH] copy-file-range: work around Linux kernel bug

[Pádraig Brady]

On 16/01/2022 18:06, Paul Eggert wrote:
> On 1/16/22 05:37, Pádraig Brady wrote:
> > This looks like the replacement will only be used when the build system
> > uses an older kernel?
> > If so this seems brittle. Consider the case where el7 rpms are being
> > built on
> > central build systems with newer kernels.
>
> It doesn't run any code on the newer kernels, right? It merely compiles.
> If the compilation environment says "this is being compiled for kernel
> 5.3", surely the generated code can assume 5.3 or later.

Oh right. I guess the build farm would use the oldest kernel headers for this 
reason.
I.e. the replacement code would be built as long as appropriate kernel headers
were installed.  This may be a gotcha for some build / deployment setups,
but that would be unusual, so this is the right default.
I'm just extra paranoid about ensuring copy routines are robust.

Sorry for the noise.

thanks,
Pádraig