linux-kernel - Re: [PATCH] drivers: pnp: proc.c: Removed unnecessary varibles

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Message-ID: <YIZIHR0ZQPXFkOH1@unreal>
Date:   Mon, 26 Apr 2021 07:57:01 +0300
From:   Leon Romanovsky <leon@...nel.org>
To:     Shuah Khan <skhan@...uxfoundation.org>
Cc:     Anupama K Patil <anupamakpatil123@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Adam <developer@...sty.dev>, bkkarthik@...u.pes.edu,
        gregkh@...uxfoundation.org, kernelnewbies@...nelnewbies.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH] drivers: pnp: proc.c: Removed unnecessary varibles

On Fri, Apr 23, 2021 at 03:08:03PM -0600, Shuah Khan wrote:
> On 4/22/21 12:03 PM, Anupama K Patil wrote:
> > de, e are two variables of the type 'struct proc_dir_entry'
> > which can be removed to save memory. This also fixes a coding style
> > issue reported by checkpatch where we are suggested to make assignment
> > outside the if statement.
> > 
> 
> Sounds like a reasonable change.

It is unclear how much changes to ISA code are welcomed.
According to the Wikipedia, even Windows Vista disabled ISA PnP by default.
https://en.wikipedia.org/wiki/Legacy_Plug_and_Play#Specifications

> 
> > Signed-off-by: Anupama K Patil <anupamakpatil123@...il.com>
> > ---
> >   drivers/pnp/isapnp/proc.c | 13 ++++++-------
> >   1 file changed, 6 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> > index 785a796430fa..1ae458c02656 100644
> > --- a/drivers/pnp/isapnp/proc.c
> > +++ b/drivers/pnp/isapnp/proc.c
> > @@ -57,21 +57,20 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
> >   static int isapnp_proc_attach_device(struct pnp_dev *dev)
> >   {
> >   	struct pnp_card *bus = dev->card;
> > -	struct proc_dir_entry *de, *e;
> >   	char name[16];
> > -	if (!(de = bus->procdir)) {
> > +	if (!bus->procdir) {
> >   		sprintf(name, "%02x", bus->number);
> 
> It would make sense to change this to scnprintf()
> 
> > -		de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> > -		if (!de)
> > +		bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> > +		if (!bus->procdir)
> >   			return -ENOMEM;
> >   	}
> >   	sprintf(name, "%02x", dev->number);
> 
> It would make sense to change this to scnprintf()
> 
> > -	e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
> > +	dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
> >   					    &isapnp_proc_bus_proc_ops, dev);
> > -	if (!e)
> > +	if (!dev->procent)
> >   		return -ENOMEM;
> 
> Shouldn't the procdir be deleted when proc_create_data() fails?

It needs but only if proc_mkdir() was called in this function.

Thanks

> 
> > -	proc_set_size(e, 256);
> > +	proc_set_size(dev->procent, 256);
> >   	return 0;
> >   }
> > 
> 
> Note that isapnp_proc_init() doesn't check isapnp_proc_attach_device()
> return and handle errors and cleanup.
> 
> thanks,
> -- Shuah
> 
> 
> 
> _______________________________________________
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> Kernelnewbies@...nelnewbies.org
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