Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Sender: subashab=codeaurora.org@mg.codeaurora.org
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Thu, 22 Apr 2021 17:28:06 -0600
From:   subashab@codeaurora.org
To:     Alex Elder <elder@linaro.org>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Sean Tranchetti <stranche@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Daniele Palmas <dnlplm@gmail.com>,
        Aleksander Morgado <aleksander@aleksander.es>,
        Loic Poulain <loic.poulain@linaro.org>
Subject: Re: [PATCH] net: qualcomm: rmnet: Allow partial updates of IFLA_FLAGS
In-Reply-To: <76db0c51-15be-2d27-00a7-c9f8dc234816@linaro.org>
References: <20210422182045.1040966-1-bjorn.andersson@linaro.org>
 <76db0c51-15be-2d27-00a7-c9f8dc234816@linaro.org>
Message-ID: <89526b9845cc86143da2221fc2445557@codeaurora.org>
User-Agent: Roundcube Webmail/1.3.9
Precedence: bulk

On 2021-04-22 12:29, Alex Elder wrote:
> On 4/22/21 1:20 PM, Bjorn Andersson wrote:
>> The idiomatic way to handle the changelink flags/mask pair seems to be
>> allow partial updates of the driver's link flags. In contrast the 
>> rmnet
>> driver masks the incoming flags and then use that as the new flags.
>> 
>> Change the rmnet driver to follow the common scheme, before the
>> introduction of IFLA_RMNET_FLAGS handling in iproute2 et al.
> 
> I like this a lot.  It should have been implemented this way
> to begin with; there's not much point to have the mask if
> it's only applied to the passed-in value.
> 
> KS, are you aware of *any* existing user space code that
> would not work correctly if this were accepted?
> 
> I.e., the way it was (is), the value passed in *assigns*
> the data format flags.  But with Bjorn's changes, the
> data format flags would be *updated* (i.e., any bits not
> set in the mask field would remain with their previous
> value).
> 
> Reviewed-by: Alex Elder <elder@linaro.org>

What rmnet functionality which was broken without this change.
That doesnt seem to be listed in this patch commit text.

If this is an enhancement, then patch needs to be targeted to net-next
instead of net