Messages in this thread | | | From | Dan Williams <> | Date | Wed, 10 Feb 2021 20:40:52 -0800 | Subject | Re: [PATCH v2 4/8] cxl/mem: Add basic IOCTL interface |
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On Wed, Feb 10, 2021 at 10:47 AM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: [..] > > +#define CXL_CMDS \ > > + ___C(INVALID, "Invalid Command"), \ > > + ___C(IDENTIFY, "Identify Command"), \ > > + ___C(MAX, "Last command") > > + > > +#define ___C(a, b) CXL_MEM_COMMAND_ID_##a > > +enum { CXL_CMDS }; > > + > > +#undef ___C > > +#define ___C(a, b) { b } > > +static const struct { > > + const char *name; > > +} cxl_command_names[] = { CXL_CMDS }; > > +#undef ___C > > Unless there are going to be a lot of these, I'd just write them out long hand > as much more readable than the macro magic.
This macro magic isn't new to Linux it was introduced with ftrace:
See "cpp tricks and treats": https://lwn.net/Articles/383362/
> > enum { > CXL_MEM_COMMAND_ID_INVALID, > CXL_MEM_COMMAND_ID_IDENTIFY, > CXL_MEM_COMMAND_ID_MAX > }; > > static const struct { > const char *name; > } cxl_command_names[] = { > [CXL_MEM_COMMAND_ID_INVALID] = { "Invalid Command" }, > [CXL_MEM_COMMAND_ID_IDENTIFY] = { "Identify Comamnd" }, > /* I hope you never need the Last command to exist in here as that sounds like a bug */ > }; > > That's assuming I actually figured the macro fun out correctly. > To my mind it's worth doing this stuff for 'lots' no so much for 3.
The list will continue to expand, and it eliminates the "did you remember to update cxl_command_names" review burden permanently.
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