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Date: Mon, 2 Mar 2026 21:24:13 +0200
From: Leon Romanovsky <leon@kernel.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>,
	linux-rdma@vger.kernel.org,
	Selvin Xavier <selvin.xavier@broadcom.com>,
	Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>,
	patches@lists.linux.dev
Subject: Re: [PATCH v2 00/13] Provide udata helpers and use them in bnxt_re
Message-ID: <20260302192413.GS12611@unreal>
References: <0-v2-13af4a900857+4f13-bnxt_re_uapi_jgg@nvidia.com>
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In-Reply-To: <0-v2-13af4a900857+4f13-bnxt_re_uapi_jgg@nvidia.com>

On Thu, Feb 26, 2026 at 09:11:03PM -0400, Jason Gunthorpe wrote:
> Add new helpers that entirely execute the expected common patterns for
> driver data uAPI forward and backwards compatibility so that drivers don't
> have to open code these.

<...>

> Since bnxt_re has never implemented these rules correctly and now does,
> provide a UCTX flag to tell userspace about it. If
> BNXT_RE_UCNTX_CMASK_UAPI_COMPAT_SUPPORTED is not set then userspace must
> not use any request or response fields beyond the current kernel uAPI.
> 
> Using any new fields is only possible on kernels with the flag.

Does a similar flag exist in any other driver? If so, we should consider
making it global to ib_uverbs. If not, keeping it bnxt_re‑specific is
sufficient.

Thanks

> 
> A series converting all drivers to these new helpers is on github, I will
> send it later:
> 
> https://github.com/jgunthorpe/linux/commits/rdma_uapi/