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

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Message-ID: <20210428122614.xhqgv5bneytooczk@burgerking>
Date:   Wed, 28 Apr 2021 17:56:14 +0530
From:   bkkarthik <bkkarthik@...u.pes.edu>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     Jaroslav Kysela <perex@...ex.cz>,
        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

On 21/04/28 03:21PM, Leon Romanovsky wrote:
> 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.

Yes, pci_proc_detach_device() and pci_proc_detach_bus() are both one-line functions as well.
I don't mean to question working code, we only tried to do something similar here for ISA.

thanks,

karthik

> 
> > 
> > 
> > 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.

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