RE: [PATCH net-next v2 5/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum trailer

[David Laight]

...
> >> -	if (!csum_trailer->valid) {
> >> +	if (!u8_get_bits(csum_trailer->flags, MAP_CSUM_DL_VALID_FMASK)) {
> >
> > Is that just an overcomplicated way of saying:
> > 	if (!(csum_trailer->flags & MAP_CSUM_DL_VALID_FMASK)) {
> 
> Yes it is.  I defined and used all the field masks in a
> consistent way, but I do think it will read better the
> way you suggest.  Bjorn also asked me privately whether
> GENMASK(15, 15) was just the same as BIT(15) (it is).
> 
> I will post version 3 of the series, identifying which
> fields are single bit/Boolean.  For those I will define
> the value using BIT() and will set/extract using simple
> AND/OR operators.  I won't use the _FMASK suffix on such
> fields.

Even for the checksum offset a simple 'offset << CONSTANT'
is enough.
If it is the bottom bits then even that isn't really needed.
You might want to mask off high bits - but that is an error
path that needs to have been checked earlier.

	David

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