Date:   Sun, 12 Mar 2023 17:57:03 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Cc:     linux-kernel@vger.kernel.org, jgg@ziepe.ca,
        Liam.Howlett@Oracle.com, jhubbard@nvidia.com, david@redhat.com,
        willy@infradead.org,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Suren Baghdasaryan <surenb@google.com>
Subject: Re: [RFC PATCH v1 1/1] linux: mm_types: allow to modified the
 vm_flags in vm_area_struct
Message-Id: <20230312175703.d8d8e0192387dfa9592ee8e5@linux-foundation.org>
In-Reply-To: <20230312224250.425727-1-vincenzopalazzodev@gmail.com>
References: <20230312224250.425727-1-vincenzopalazzodev@gmail.com>
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On Sun, 12 Mar 2023 23:42:50 +0100 Vincenzo Palazzo <vincenzopalazzodev@gmail.com> wrote:

> With 6.3-rc1 is not possible to build the following drivers

Well, let's cc Suren who actually wrote bc292ab00f6c ("mm: introduce
vma->vm_flags wrapper functions").

> - nvidia, that the compilation returns the following errors
> 
> - vboxhost/7.0.6_OSE where the build fails with the following errors
> 
> ...
>
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -497,7 +497,7 @@ struct vm_area_struct {
>  	 * To modify use vm_flags_{init|reset|set|clear|mod} functions.
>  	 */
>  	union {
> -		const vm_flags_t vm_flags;
> +		vm_flags_t vm_flags;
>  		vm_flags_t __private __vm_flags;
>  	};

These out-of-tree drivers should be converted to use the wrappers which
bc292ab00f6c added.  Their maintainers have a couple of months to do
this before bc292ab00f6c is released in 6.3.

It's unfortunate.  I guess it would be better if we were to find a way
to permit these drivers to compile OK but to generate warnings, as an
interim thing for six months or so.  Perhaps there's some clever way.