linux-kernel - Re: [PATCH V6 4/7] OF: properties: Implement get_match

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

Message-ID: <20171208090926.2fb362ef@karo-electronics.de>
Date:   Fri, 8 Dec 2017 09:09:26 +0100
From:   Lothar Waßmann <LW@...O-electronics.de>
To:     Sinan Kaya <okaya@...eaurora.org>
Cc:     devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        timur@...eaurora.org, open list <linux-kernel@...r.kernel.org>,
        linux-acpi@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        dmaengine@...r.kernel.org, Frank Rowand <frowand.list@...il.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V6 4/7] OF: properties: Implement get_match_data()
 callback

Hi,

On Thu, 7 Dec 2017 12:50:50 -0500 Sinan Kaya wrote:
> On 12/7/2017 10:20 AM, Lothar Waßmann wrote:
> > Hi,
> > 
> > On Thu, 7 Dec 2017 09:45:31 -0500 Sinan Kaya wrote:
> >> On 12/7/2017 8:10 AM, Lothar Waßmann wrote:
> >>>> +void *of_fwnode_get_match_data(const struct fwnode_handle *fwnode,
> >>>> +			       struct device *dev)
> >>> Shouldn't this be 'const void *of_fwnode_get_match_data
> >>
> >> OF keeps the driver data as a (const void*) internally. ACPI keeps the
> >> driver data as kernel_ulong_t in struct acpi_device_id.
> >>
> >> I tried to find the middle ground here by converting output to void*
> >> but not keeping const.
> >>
> > It should be no problem to cast a (const void *) to an unsigned long
> > data type (without const qualifier).
> > 
> 
> It is the other way around. If I change this API to return a a (const void*),
> the device_get_match_data() function need to return a (const void *).
> 
> While implementing the ACPI piece, I have to convert an unsigned long to
> (const void *) in ACPI code so that the APIs are compatible.
> 
That's true, but I don't see any problem with that. Your
device_get_match_data() is merely a wrapper around of_device_get_match_data()
which returns a const pointer. I see no reason to change this to a
non-const pointer by the wrapper function.


Lothar Waßmann