linux-kernel - Re: [PATCH 3/9] staging: fsl-mc: add device release callback

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Date:   Fri, 3 Feb 2017 15:53:01 +0000
From:   Laurentiu Tudor <laurentiu.tudor@....com>
To:     Stuart Yoder <stuart.yoder@....com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:     "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "arnd@...db.de" <arnd@...db.de>,
        Ruxandra Ioana Radulescu <ruxandra.radulescu@....com>,
        "Roy Pledge" <roy.pledge@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "agraf@...e.de" <agraf@...e.de>,
        "Catalin Horghidan" <catalin.horghidan@....com>,
        Leo Li <leoyang.li@....com>
Subject: Re: [PATCH 3/9] staging: fsl-mc: add device release    callback



On 02/03/2017 02:02 AM, Stuart Yoder wrote:
>
>> -----Original Message-----
>> From: upstream-release-bounces@...ux.freescale.net [mailto:upstream-release-
>> bounces@...ux.freescale.net] On Behalf Of laurentiu.tudor@....com
>> Sent: Wednesday, February 01, 2017 5:43 AM
>> To: gregkh@...uxfoundation.org
>> Cc: devel@...verdev.osuosl.org; arnd@...db.de; Ruxandra Ioana Radulescu <ruxandra.radulescu@....com>;
>> Roy Pledge <roy.pledge@....com>; linux-kernel@...r.kernel.org; agraf@...e.de; Catalin Horghidan
>> <catalin.horghidan@....com>; Leo Li <leoyang.li@....com>; Stuart Yoder <stuart.yoder@....com>;
>> Laurentiu Tudor <laurentiu.tudor@....com>
>> Subject: [upstream-release] [PATCH 3/9] staging: fsl-mc: add device release callback
>>
>> From: Laurentiu Tudor <laurentiu.tudor@....com>
>>
>> When hot unplugging a mc-bus device the kernel displays
>> this pertinent message, followed by a stack dump:
>>      "Device 'foo.N' does not have a release() function,
>>       it is broken and must be fixed."
>> Add the required callback to fix.
>>
>> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@....com>
>> ---
>>   drivers/staging/fsl-mc/bus/fsl-mc-bus.c | 17 +++++++++++++++++
>>   1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/staging/fsl-mc/bus/fsl-mc-bus.c b/drivers/staging/fsl-mc/bus/fsl-mc-bus.c
>> index 7c6a43b..6601bde 100644
>> --- a/drivers/staging/fsl-mc/bus/fsl-mc-bus.c
>> +++ b/drivers/staging/fsl-mc/bus/fsl-mc-bus.c
>> @@ -419,6 +419,22 @@ bool fsl_mc_is_root_dprc(struct device *dev)
>>   	return dev == root_dprc_dev;
>>   }
>>
>> +static void fsl_mc_device_release(struct device *dev)
>> +{
>> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
>> +	struct fsl_mc_bus *mc_bus = NULL;
>> +
>> +	kfree(mc_dev->regions);
>> +
>> +	if (strcmp(mc_dev->obj_desc.type, "dprc") == 0)
>> +		mc_bus = to_fsl_mc_bus(mc_dev);
>> +
>> +	if (mc_bus)
>> +		devm_kfree(mc_dev->dev.parent, mc_bus);
>> +	else
>> +		kmem_cache_free(mc_dev_cache, mc_dev);
>> +}
>> +
>>   /**
>>    * Add a newly discovered fsl-mc device to be visible in Linux
>>    */
>> @@ -460,6 +476,7 @@ int fsl_mc_device_add(struct dprc_obj_desc *obj_desc,
>>   	device_initialize(&mc_dev->dev);
>>   	mc_dev->dev.parent = parent_dev;
>>   	mc_dev->dev.bus = &fsl_mc_bus_type;
>> +	mc_dev->dev.release = fsl_mc_device_release;
>>   	dev_set_name(&mc_dev->dev, "%s.%d", obj_desc->type, obj_desc->id);
>>
>>   	if (strcmp(obj_desc->type, "dprc") == 0) {
>> --
>
> With this patch applied, you still have this:
>
> void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
> {
>          struct fsl_mc_bus *mc_bus = NULL;
>
>          kfree(mc_dev->regions);
>
>          /*
>           * The device-specific remove callback will get invoked by device_del()
>           */
>          device_del(&mc_dev->dev);
>          put_device(&mc_dev->dev);
>
>          if (strcmp(mc_dev->obj_desc.type, "dprc") == 0)
>                  mc_bus = to_fsl_mc_bus(mc_dev);
>
>          if (mc_bus)
>                  devm_kfree(mc_dev->dev.parent, mc_bus);
>          else
>                  kmem_cache_free(mc_dev_cache, mc_dev);
> }
>
> ...i.e. you are doing the same thing in 2 places.  You
> need to remove the kfree/devm_kfree/ kmem_cache_free,
> here, no?
>

Right, thanks for spotting. I started working on a v2
of the series.

---
Best Regards, Laurentiu