linux-kernel - Re: [PATCH 2/4] staging: r8188eu: reformat long computation lines

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Message-ID: <Y0+c1ljPcD+Qr4Gd@debian-BULLSEYE-live-builder-AMD64>
Date:   Wed, 19 Oct 2022 12:14:38 +0530
From:   Deepak R Varma <drv@...lo.com>
To:     Joe Perches <joe@...ches.com>
Cc:     David Laight <David.Laight@...lab.com>,
        'Greg KH' <gregkh@...uxfoundation.org>,
        "outreachy@...ts.linux.dev" <outreachy@...ts.linux.dev>,
        "Larry.Finger@...inger.net" <Larry.Finger@...inger.net>,
        "phil@...lpotter.co.uk" <phil@...lpotter.co.uk>,
        "paskripkin@...il.com" <paskripkin@...il.com>,
        "linux-staging@...ts.linux.dev" <linux-staging@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kumarpraveen@...ux.microsoft.com" <kumarpraveen@...ux.microsoft.com>,
        "saurabh.truth@...il.com" <saurabh.truth@...il.com>
Subject: Re: [PATCH 2/4] staging: r8188eu: reformat long computation lines

On Tue, Oct 18, 2022 at 11:38:22PM -0700, Joe Perches wrote:
> On Wed, 2022-10-19 at 11:47 +0530, Deepak R Varma wrote:
> > On Tue, Oct 18, 2022 at 10:43:07PM -0700, Joe Perches wrote:
> > > On Tue, 2022-10-18 at 18:12 +0530, Deepak R Varma wrote:
> > > > On Tue, Oct 18, 2022 at 11:21:26AM +0000, David Laight wrote:
> > > > > From: Greg KH
> > > > > > Sent: 17 October 2022 15:10
> > > > > >
> > > > > > On Mon, Oct 17, 2022 at 06:52:50PM +0530, Deepak R Varma wrote:
> > > > > > > Reformat long running computation instructions to improve code readability.
> > > > > > > Address following checkpatch script complaints:
> > > > > > > 	CHECK: line length of 171 exceeds 100 columns
> > > > > > > 	CHECK: line length of 113 exceeds 100 columns
> > > []
> > > > > > > diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
> > > []
> > > > > > > @@ -211,8 +211,10 @@ static int __nat25_network_hash(unsigned char *network_addr)
> > > > > > >  	} else if (network_addr[0] == NAT25_IPX) {
> > > > > > >  		unsigned long x;
> > > > > > >
> > > > > > > -		x = network_addr[1] ^ network_addr[2] ^ network_addr[3] ^ network_addr[4] ^
> > > > > > network_addr[5] ^
> > > > > > > -			network_addr[6] ^ network_addr[7] ^ network_addr[8] ^ network_addr[9] ^
> > > > > > network_addr[10];
> > > > > > > +		x = network_addr[1] ^ network_addr[2] ^ network_addr[3] ^
> > > > > >
> > > > > > Why not go out to [4] here and then you are one line shorter?
> > > > >
> > > > > and/or use a shorter variable name....
> > > > Hi David,
> > > > I have already re-submitted the patch set with 4 in line arrangement. Do you
> > > > still suggest using shorter variable names?
> > >
> > > Assuming this code is not performance sensitive, I suggest not just
> > > molifying checkpatch but perhaps improving the code by adding a helper
> > > function something like:
> > >
> > > u8 xor_array_u8(u8 *x, size_t len)
> > > {
> > > 	size_t i;
> > > 	u8 xor = x[0];
> > >
> > > 	for (i = 1; i < len; i++)
> > > 		xor ^= x[i];
> > >
> > > 	return xor;
> > > }
> > >
> > > so for instance this could be:
> > >
> > > 		x = xor_array_u8(&network_addr[1], 10);
> > >
> >
> > Hi Joe,
> > Great suggestion. Thank you.
> > Is there a way to confirm that this improvement won't impact performance? Will I
> > need any specific hardware / device to run tests?
>
> I suggest reading the code to see if the uses are in some fast path.

Sounds good. Thank you for your guidance.

>