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    SubjectRe: [PATCH v4] coding-style: Clarify the expectations around bool
    On Thu, Jan 10, 2019 at 11:48:13PM +0000, Jason Gunthorpe wrote:
    > +The Linux kernel bool type is an alias for the C99 _Bool type. bool values can
    > +only evaluate to 0 or 1, and implicit or explicit conversion to bool
    > +automatically converts the value to true or false. When using bool types the
    > +!! construction is not needed, which eliminates a class of bugs.
    > +
    > +When working with bool values the true and false definitions should be used
    > +instead of 0 and 1.
    > +
    > +bool function return types and stack variables are always fine to use whenever
    > +appropriate. Use of bool is encouraged to improve readability and is often a
    > +better option than 'int' for storing boolean values.

    It's awkward to start a sentence with a lower case letter. How about
    rephrasing this paragraph and the following one as:

    Using bool as the return type of a function or as a variable is always
    fine when appropriate. It often improves readability and is a better option
    than int for storing boolean values. Using bool in data structures is
    more debatable; its size and alignment can vary between architectures.

    > +Do not use bool if cache line layout or size of the value matters, its size
    > +and alignment varies based on the compiled architecture. Structures that are
    > +optimized for alignment and size should not use bool.
    > +
    > +If a structure has many true/false values, consider consolidating them into a
    > +bitfield with 1 bit members, or using an appropriate fixed width type, such as
    > +u8.

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