linux-kernel - Re: [PATCH 2/7] of: factor out of_map

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <zz7n3x7e7dsqgfw7qgppeaqnb3uz3i5bzd3tybzbv6q7zmdcgk@pojvxhui7q4v>
Date: Thu, 5 Feb 2026 16:53:43 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Vijayanand Jitta <vijayanand.jitta@....qualcomm.com>
Cc: Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Vikash Garodia <vikash.garodia@....qualcomm.com>,
        Dikshita Agarwal <dikshita.agarwal@....qualcomm.com>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Bryan O'Donoghue <bod@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Saravana Kannan <saravanak@...nel.org>, Joerg Roedel <joro@...tes.org>,
        Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Stefan Schmidt <stefan.schmidt@...aro.org>,
        Hans Verkuil <hverkuil@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Vishnu Reddy <busanna.reddy@....qualcomm.com>,
        Hans Verkuil <hverkuil+cisco@...nel.org>,
        linux-arm-msm@...r.kernel.org, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        iommu@...ts.linux.dev,
        Charan Teja Kalla <charan.kalla@....qualcomm.com>
Subject: Re: [PATCH 2/7] of: factor out of_map_id() code

On Thu, Feb 05, 2026 at 01:39:54PM +0530, Vijayanand Jitta wrote:
> 
> 
> On 2/4/2026 6:41 AM, Dmitry Baryshkov wrote:
> > On Tue, Feb 03, 2026 at 03:43:58PM +0530, Vijayanand Jitta wrote:
> >>
> >>
> >> On 2/2/2026 8:22 PM, Bryan O'Donoghue wrote:
> >>> On 26/01/2026 12:25, Vikash Garodia wrote:
> >>>> From: Charan Teja Kalla <charan.kalla@....qualcomm.com>
> >>>
> >>> This commit message is confusing and inaccurate.
> >>>
> >>> First up, you're not factoring _out_ of_map_id() - factor out of_map_id() means to remove of_map_id() - you are refactoring of_map_id().
> >>>
> >>> Your patch title should be something like "refactor of_map_id() to prepare for mapping of multiple IDs to a single device"
> >>>
> >>
> >> Sure, will update the commit.
> >>
> >>>> Linux interprets multiple mappings for the same input ID as a set of
> >>>> equivalent choices to pick one. There exists usecases where these set
> >>>> must be maintained in parallel, ex: on ARM, a dynamically created child
> >>>> device(s) is referencing multiple input id's in parent iommu-map.
> >>>>
> >>>> Factor out the code where multiple mappings needs to be maintained in
> >>>> parallel can be achieved through callback from this factored out code.
> >>>
> >>> Which callback ? There is no ->function(pointer, here...); ?!
> >>>
> >>> Just make some plain and straightforward statements about what you are doing and why. There's no need to resort to dissertation-speak.
> >>>
> >>
> >> The callback in introduced in patch 2 of this series. will update the commit descripition as suggested.
> > 
> > I think, the callback was NAKed already.
> > 
> > 
> 
> I'll remove the callback and update change such that all entries of iommu-map are always scanned.
> This would handle the video usecase ( i.e; same input id's mapping to different SIDs ) and in other
> cases it would result in few additional scans in iommu-map compared to existing implementation (where
> it just returns after first input id match) , does this look fine ?

This probably means that we can also drop of_map_args.

-- 
With best wishes
Dmitry