Re: [PATCH] usb: Replace a < b ? a : b construct with min_t(type, a, b) in drivers/usb

[dmg <dmg@turingmachine.org>]

Greg KH <gregkh@linuxfoundation.org> writes:

> On Mon, Jun 17, 2019 at 04:30:50PM -0700, dmg@turingmachine.org wrote:
>> From: Daniel M German <dmg@turingmachine.org>
>>
>> Use min_t to find the minimum of two values instead of using the ?: operator.
>
> Why is min_t() needed for all of these and not just min()?

The use of min triggers a compilation warning (see below), which min_t is supposed to
address (from min_t comment: 'min()/max() macros that also do strict type-checking.. See the
"unnecessary" pointer comparison.", from include/linux/kernel')

   In file included from drivers/usb/misc/adutux.c:19:
   drivers/usb/misc/adutux.c: In function ‘adu_read’:
   ./include/linux/kernel.h:818:29: warning: comparison of distinct pointer types lacks a cast
      (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                                ^~
   ./include/linux/kernel.h:832:4: note: in expansion of macro ‘__typecheck’
      (__typecheck(x, y) && __no_side_effects(x, y))
       ^~~~~~~~~~~
   ./include/linux/kernel.h:842:24: note: in expansion of macro ‘__safe_cmp’
     __builtin_choose_expr(__safe_cmp(x, y), \
                           ^~~~~~~~~~
   ./include/linux/kernel.h:851:19: note: in expansion of macro ‘__careful_cmp’
    #define min(x, y) __careful_cmp(x, y, <)
                      ^~~~~~~~~~~~~
   drivers/usb/misc/adutux.c:382:34: note: in expansion of macro ‘min’
                        int amount = min(bytes_to_read, data_in_secondary);
                                     ^~~

[...]

> Can you break this up into one patch per driver?  That way you can
> include the proper maintainers/reviewers when you resend them.
>

I will split the patch as instructed.



> thanks,
>
> greg k-h


--
Daniel M. German                  "Beauty is the first test; there is no
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   G. H. Hardy ->                  mathematics."
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