linux-kernel - Re: [RFC 13/19] staging: qlge: rewrite do while loop as for loop in qlge_sem

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Message-ID: <f7beb9aee00a1cdb8dd97a49a36abd60d58279f2.camel@perches.com>
Date:   Wed, 30 Jun 2021 03:58:06 -0700
From:   Joe Perches <joe@...ches.com>
To:     Coiby Xu <coiby.xu@...il.com>,
        Dan Carpenter <dan.carpenter@...cle.com>
Cc:     linux-staging@...ts.linux.dev, netdev@...r.kernel.org,
        Benjamin Poirier <benjamin.poirier@...il.com>,
        Shung-Hsi Yu <shung-hsi.yu@...e.com>,
        Manish Chopra <manishc@...vell.com>,
        "supporter:QLOGIC QLGE 10Gb ETHERNET DRIVER" 
        <GR-Linux-NIC-Dev@...vell.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 13/19] staging: qlge: rewrite do while loop as for loop in
 qlge_sem_spinlock

On Thu, 2021-06-24 at 19:22 +0800, Coiby Xu wrote:
> On Tue, Jun 22, 2021 at 10:20:36AM +0300, Dan Carpenter wrote:
> > On Mon, Jun 21, 2021 at 09:48:56PM +0800, Coiby Xu wrote:
> > > Since wait_count=30 > 0, the for loop is equivalent to do while
> > > loop. This commit also replaces 100 with UDELAY_DELAY.
[]
> > > diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
[]
> > > @@ -140,12 +140,13 @@ static int qlge_sem_trylock(struct qlge_adapter *qdev, u32 sem_mask)
> > >  int qlge_sem_spinlock(struct qlge_adapter *qdev, u32 sem_mask)
> > >  {
> > >  	unsigned int wait_count = 30;
> > > +	int count;
> > > 
> > > -	do {
> > > +	for (count = 0; count < wait_count; count++) {
> > >  		if (!qlge_sem_trylock(qdev, sem_mask))
> > >  			return 0;
> > > -		udelay(100);
> > > -	} while (--wait_count);
> > > +		udelay(UDELAY_DELAY);
> > 
> > This is an interesting way to silence the checkpatch udelay warning.  ;)
> 
> I didn't know this could silence the warning :)

It also seems odd to have unsigned int wait_count and int count.

Maybe just use 30 in the loop without using wait_count at all.

I also think using UDELAY_DELAY is silly and essentially misleading
as it's also used as an argument value for mdelay

$ git grep -w UDELAY_DELAY
drivers/staging/qlge/qlge.h:#define UDELAY_DELAY 100
drivers/staging/qlge/qlge_main.c:               udelay(UDELAY_DELAY);
drivers/staging/qlge/qlge_main.c:               udelay(UDELAY_DELAY);
drivers/staging/qlge/qlge_mpi.c:                mdelay(UDELAY_DELAY);
drivers/staging/qlge/qlge_mpi.c:                mdelay(UDELAY_DELAY);
drivers/staging/qlge/qlge_mpi.c:                mdelay(UDELAY_DELAY); /* 100ms */