netdev - RE: [PATCH net] qede: fix interrupt coalescing configuration

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Message-ID: <BY3PR18MB46125E85746A9AFB8E050B43ABA09@BY3PR18MB4612.namprd18.prod.outlook.com>
Date:   Thu, 16 Feb 2023 15:06:14 +0000
From:   Manish Chopra <manishc@...vell.com>
To:     David Laight <David.Laight@...LAB.COM>,
        "kuba@...nel.org" <kuba@...nel.org>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Ariel Elior <aelior@...vell.com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Bhaskar Upadhaya <bupadhaya@...vell.com>,
        "David S . Miller" <davem@...emloft.net>
Subject: RE: [PATCH net] qede: fix interrupt coalescing configuration

> -----Original Message-----
> From: David Laight <David.Laight@...LAB.COM>
> Sent: Thursday, February 16, 2023 6:11 PM
> To: Manish Chopra <manishc@...vell.com>; kuba@...nel.org
> Cc: netdev@...r.kernel.org; Ariel Elior <aelior@...vell.com>;
> stable@...r.kernel.org; Bhaskar Upadhaya <bupadhaya@...vell.com>;
> David S . Miller <davem@...emloft.net>
> Subject: [EXT] RE: [PATCH net] qede: fix interrupt coalescing configuration
> 
> External Email
> 
> ----------------------------------------------------------------------
> From: Manish Chopra
> > Sent: 16 February 2023 11:55
> >
> > On default driver load device gets configured with unexpected higher
> > interrupt coalescing values instead of default expected values as
> > memory allocated from krealloc() is not supposed to be zeroed out and
> > may contain garbage values.
> >
> > Fix this by allocating the memory of required size first with
> > kcalloc() and then use krealloc() to resize and preserve the contents
> > across down/up of the interface.
> 
> Doesn't any extra memory allocated by krealloc() need to be zerod ?

Hi David,

Driver will not attempt to allocate the size (using krealloc()) which is greater than the size
initially allocated by kcalloc() ever.

Thanks,
Manish

> 
> 	David
> 
> >
> > Signed-off-by: Manish Chopra <manishc@...vell.com>
> > Fixes: b0ec5489c480 ("qede: preserve per queue stats across up/down of
> > interface")
> > Cc: stable@...r.kernel.org
> > Cc: Bhaskar Upadhaya <bupadhaya@...vell.com>
> > Cc: David S. Miller <davem@...emloft.net>
> > Link:
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.redhat.c
> > om_show-5Fbug.cgi-3Fid-
> 3D2160054&d=DwIFaQ&c=nKjWec2b6R0mOyPaz7xtfQ&r=b
> > MTgx2X48QVXyXOEL8ALyI4dsWoR-m74c5n3d-
> ruJI8&m=yxUlxYqV9xzhL4ZcgCffdrxKT
> >
> 6qVQqXE6JdE28XtyOwxInnkbtBiM1lxjYJCI0Wm&s=uz96PudLovEFy3W0_IpBM
> wBWwGkl
> > 88SQR0pJXP0k-5I&e=
> > Signed-off-by: Alok Prasad <palok@...vell.com>
> > Signed-off-by: Ariel Elior <aelior@...vell.com>
> > ---
> >  drivers/net/ethernet/qlogic/qede/qede_main.c | 11 +++++++++--
> >  1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c
> > b/drivers/net/ethernet/qlogic/qede/qede_main.c
> > index 953f304b8588..af39513db1ba 100644
> > --- a/drivers/net/ethernet/qlogic/qede/qede_main.c
> > +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
> > @@ -970,8 +970,15 @@ static int qede_alloc_fp_array(struct qede_dev
> *edev)
> >  		goto err;
> >  	}
> >
> > -	mem = krealloc(edev->coal_entry, QEDE_QUEUE_CNT(edev) *
> > -		       sizeof(*edev->coal_entry), GFP_KERNEL);
> > +	if (!edev->coal_entry) {
> > +		mem = kcalloc(QEDE_MAX_RSS_CNT(edev),
> > +			      sizeof(*edev->coal_entry), GFP_KERNEL);
> > +	} else {
> > +		mem = krealloc(edev->coal_entry,
> > +			       QEDE_QUEUE_CNT(edev) * sizeof(*edev-
> >coal_entry),
> > +			       GFP_KERNEL);
> > +	}
> > +
> >  	if (!mem) {
> >  		DP_ERR(edev, "coalesce entry allocation failed\n");
> >  		kfree(edev->coal_entry);
> > --
> > 2.27.0
> 
> -
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