linux-kernel - Re: [PATCH 2/4] fpga: manager: change api, don't use drvdata

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Date:   Fri, 27 Apr 2018 16:38:18 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Alan Tull <atull@...nel.org>
Cc:     Moritz Fischer <mdf@...nel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>, linux-fpga@...r.kernel.org,
        linux-doc@...r.kernel.org, Michal Simek <michal.simek@...inx.com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/4] fpga: manager: change api, don't use drvdata

On 04/27/2018 04:30 PM, Alan Tull wrote:
> On Fri, Apr 27, 2018 at 1:26 PM, Florian Fainelli <f.fainelli@...il.com> wrote:
>> On 04/26/2018 06:26 PM, Moritz Fischer wrote:
>>> From: Alan Tull <atull@...nel.org>
>>>
>>> Change fpga_mgr_register to not set or use drvdata.  This supports
>>> the case where a PCIe device has more than one manager.
>>>
>>> Add fpga_mgr_create/free functions.  Change fpga_mgr_register and
>>> fpga_mgr_unregister functions to take the mgr struct as their only
>>> parameter.
>>>
>>>   struct fpga_manager *fpga_mgr_create(struct device *dev,
>>>                 const char *name,
>>>                 const struct fpga_manager_ops *mops,
>>>                 void *priv);
>>>   void fpga_mgr_free(struct fpga_manager *mgr);
>>>   int fpga_mgr_register(struct fpga_manager *mgr);
>>>   void fpga_mgr_unregister(struct fpga_manager *mgr);
>>>
>>> Update the drivers that call fpga_mgr_register with the new API.
>>
>> Apologies for chiming in so late, this commit does not make it clear
>> that fpga_mgr_unregister() now also free the 'mgr' argument by calling
>> fpga_mgr_free(), this is kind of detail, but an API should make that
>> clear IMHO.
> 
> If people follow the usage information, in
> Documentation/fpga/fpga-mgr.txt, they'll do the right thing.  But I
> can add a patch that clarifies the description of fpga_mgr_unregister
> in fpga-mgr.c that it "unregisters and frees" the manager.

Just mentioning that because not all APIs do this, take the network
devices: there is an unregister_netdev() and a free_netdev(). Either way
is fine with me as long as it is documented as such, I had to look at
the API implementation to figure out that, no, all the drivers were not
leaking their fpga_manager instance in their .remove() function :)
-- 
Florian