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Date:   Sun, 27 Nov 2022 18:38:39 -0800
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Subject: Re: [PATCH 1/5] driver core: make struct class.dev_uevent() take a
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To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        Luis Chamberlain <mcgrof@kernel.org>,
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References: <20221123122523.1332370-1-gregkh@linuxfoundation.org>
 <d448b944-708a-32d4-37d7-0be16ee5f73c@acm.org> <Y4NqAJW5V0tAP8ax@kroah.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <Y4NqAJW5V0tAP8ax@kroah.com>
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On 11/27/22 05:45, Greg Kroah-Hartman wrote:
> On Fri, Nov 25, 2022 at 03:51:11PM -0800, Bart Van Assche wrote:
>> On 11/23/22 04:25, Greg Kroah-Hartman wrote:
>>> diff --git a/include/linux/mISDNif.h b/include/linux/mISDNif.h
>>> index 7dd1f01ec4f9..7aab4a769736 100644
>>> --- a/include/linux/mISDNif.h
>>> +++ b/include/linux/mISDNif.h
>>> @@ -586,7 +586,7 @@ extern struct mISDNclock *mISDN_register_clock(char *, int, clockctl_func_t *,
>>>    						void *);
>>>    extern void	mISDN_unregister_clock(struct mISDNclock *);
>>> -static inline struct mISDNdevice *dev_to_mISDN(struct device *dev)
>>> +static inline struct mISDNdevice *dev_to_mISDN(const struct device *dev)
>>>    {
>>>    	if (dev)
>>>    		return dev_get_drvdata(dev);
>>
>> Why does the dev_to_mISDN() function drop constness? I haven't found an
>> explanation for this in the cover letter.
> 
> I agree, this is going to be fixed up, see the thread starting here:
> 	https://lore.kernel.org/r/Y34+V2bCDdqujBDk@kroah.com
> 
> I'll work on making a const / non const version for these so that we
> don't loose the marking.
> 
> Oh wait, no, this function is fine, it's not modifying the device
> structure at all, and only returning the pointer in the private data
> stored in the device.  There is no loss of const-ness here.

Hi Greg,

This is what I found in include/linux/mISDNif.h:

struct mISDNdevice {
	struct mISDNchannel	D;
	u_int			id;
	u_int			Dprotocols;
	u_int			Bprotocols;
	u_int			nrbchan;
	u_char			channelmap[MISDN_CHMAP_SIZE];
	struct list_head	bchannels;
	struct mISDNchannel	*teimgr;
	struct device		dev;
};

As one can see 'dev' is a member of struct mISDNdevice. I still think 
that dev_to_mISDN() drops constness. Did I perhaps overlook something?

Bart.