Re: [PATCH] verbs: fix compilation warning with C++20

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, Jun 09, 2023 at 05:31:47PM +0200, Daniel Vacek wrote:
> Our customer reported the below warning whe using Clang v16.0.4 and C++20,
> on a code that includes the header "/usr/include/infiniband/verbs.h":
> 
> error: bitwise operation between different enumeration types ('ibv_access_flags' and
> 'ib_uverbs_access_flags') is deprecated [-Werror,-Wdeprecated-enum-enum-conversion]
>                 mem->mr = ibv_reg_mr(dev->pd, (void*)start, len, IBV_ACCESS_LOCAL_WRITE);
>                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /usr/include/infiniband/verbs.h:2514:19: note: expanded from macro 'ibv_reg_mr'
>                              ((access) & IBV_ACCESS_OPTIONAL_RANGE) == 0))
>                               ~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
> 
> According to the article "Clang 11 warning: Bitwise operation between different
> enumeration types is deprecated":
> 
> C++20's P1120R0 deprecated bitwise operations between different enums. Such code is
> likely to become ill-formed in C++23. Clang 11 warns about such cases. It should be fixed.

There should be a cast to an integer in the macro, we can't know what
the user will pass in there and it may not be that enum.

Jason