> On Nov 27, 2018, at 10:48 AM, Roman Kagan <rkagan@xxxxxxxxxxxxx> wrote: > > 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 :) Last time I tried to push a change from bitmasks to bitfields I failed: https://lkml.org/lkml/2014/9/16/245 On a different note: how come all of the hyper-v structs are not marked with the “packed" attribute?
