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

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Message-ID: <19e8bd56-e24d-551e-9de2-57675541ee3f@perex.cz>
Date:   Wed, 28 Apr 2021 14:30:14 +0200
From:   Jaroslav Kysela <perex@...ex.cz>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     bkkarthik <bkkarthik@...u.pes.edu>,
        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 28. 04. 21 v 14:21 Leon Romanovsky napsal(a):
> On Wed, Apr 28, 2021 at 02:04:49PM +0200, Jaroslav Kysela wrote:
>> 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);
> 
> He talks about isapnp_proc_detach_*() functions.

But only this patch introduced those functions. The pci_proc_init() code does
not call pci_proc_detach_*() functions and ignores the allocation errors, too.
I don't think that this cleanup code is required.

					Jaroslav

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