linux-kernel - Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices

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Message-ID: <59a5d631-6658-2034-06c4-467520b5b9f7@perex.cz>
Date:   Wed, 28 Apr 2021 14:04:49 +0200
From:   Jaroslav Kysela <perex@...ex.cz>
To:     bkkarthik <bkkarthik@...u.pes.edu>,
        Leon Romanovsky <leon@...nel.org>
Cc:     Anupama K Patil <anupamakpatil123@...il.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        skhan@...uxfoundation.org, gregkh@...uxfoundation.org,
        kernelnewbies@...nelnewbies.org
Subject: Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching
 devices

Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
> On 21/04/26 08:04AM, Leon Romanovsky wrote:
>> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
>>> isapnp_proc_init() does not look at the return value from
>>> isapnp_proc_attach_device(). Check for this return value in
>>> isapnp_proc_detach_device().
>>>
>>> Cleanup in isapnp_proc_detach_device and
>>> isapnp_proc_detach_bus() for cleanup.
>>>
>>> Changed sprintf() to the kernel-space function scnprintf() as it returns
>>> the actual number of bytes written.
>>>
>>> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
>>> save memory.
>>
>> What exactly do you fix for such an old code?
> 
> I was not aware that this code is so old. This fix was made after checkpatch reported assignment inside an if-statement.
> Please ignore this patch if th change is not necessary as the code is probably not being used anywhere :)
> 
> Maybe the code has to be marked as obsolete in the MAINTAINERS file to prevent patches being sent?
> 
>>
>>>
>>> Suggested-by: Shuah Khan <skhan@...uxfoundation.org>
>>> Co-developed-by: B K Karthik <bkkarthik@...u.pes.edu>
>>> Signed-off-by: B K Karthik <bkkarthik@...u.pes.edu>
>>> Signed-off-by: Anupama K Patil <anupamakpatil123@...il.com>
>>> ---
>>>  drivers/pnp/isapnp/proc.c | 40 +++++++++++++++++++++++++++++----------
>>>  1 file changed, 30 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
>>> index 785a796430fa..46ebc24175b7 100644
>>> --- a/drivers/pnp/isapnp/proc.c
>>> +++ b/drivers/pnp/isapnp/proc.c
>>> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
>>>  	.proc_read	= isapnp_proc_bus_read,
>>>  };
>>>  
>>> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
>>> +{
>>> +	proc_remove(dev->procent);
>>> +	dev->procent = NULL;
>>> +	return 0;
>>> +}
>>> +
>>> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
>>> +{
>>> +	proc_remove(bus->procdir);
>>> +	return 0;
>>> +}
>>
>> Please don't add one line functions that are called only once and have
>> return value that no one care about it.
> 
> These were only intended for a clean-up job, the idea of this function came from how PCI handles procfs.
> Maybe those should be changed?

Which code you refer? I see:

       for_each_pci_dev(dev)
                pci_proc_attach_device(dev);


The error codes are ignored, too. It does not harm, if proc entries are not
created (in this case - the system is unstable anyway). We should concentrate
only to the wrong pointers usage.

						Jaroslav

-- 
Jaroslav Kysela <perex@...ex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.