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

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Date:   Fri, 3 Feb 2017 00:02:50 +0000
From:   Stuart Yoder <stuart.yoder@....com>
To:     Laurentiu Tudor <laurentiu.tudor@....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>,
        "Laurentiu Tudor" <laurentiu.tudor@....com>
Subject: RE: [PATCH 3/9] staging: fsl-mc: add device release    callback


> -----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?

Stuart