Re: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h

[Roman Kagan]

On Tue, Nov 27, 2018 at 02:10:49PM +0100, Vitaly Kuznetsov wrote:
> Roman Kagan <rkagan@xxxxxxxxxxxxx> writes:
> > On Mon, Nov 26, 2018 at 04:47:29PM +0100, Vitaly Kuznetsov wrote:
> > I personally tend to prefer masks over bitfields, so I'd rather do the
> > consolidation in the opposite direction: use the definitions in
> > hyperv-tlfs.h and replace those unions/bitfields elsewhere.  (I vaguely
> > remember posting such a patchset a couple of years ago but I lacked the
> > motivation to complete it).
> 
> Are there any known advantages of using masks over bitfields or the
> resulting binary code is the same?

Strictly speaking bitwise ops are portable while bitfields are not, but
I guess this is not much of an issue with gcc which is dependable to
produce the right thing.

I came to dislike the bitfields for the false feeling of atomicity of
assignment while most of the time they are read-modify-write operations.

And no, I don't feel strong about it, so if nobody backs me on this I
give up :)

Roman.