linux-kernel - Re: [PATCH net-next v2] net: mvpp2: Don't use dynamic allocs for local variables

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Date:   Wed, 21 Mar 2018 22:14:48 +0100
From:   Maxime Chevallier <maxime.chevallier@...tlin.com>
To:     Yan Markman <ymarkman@...vell.com>
Cc:     "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Antoine Tenart <antoine.tenart@...tlin.com>,
        "thomas.petazzoni@...tlin.com" <thomas.petazzoni@...tlin.com>,
        "gregory.clement@...tlin.com" <gregory.clement@...tlin.com>,
        "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
        Nadav Haklai <nadavh@...vell.com>,
        "Stefan Chulski" <stefanc@...vell.com>,
        "mw@...ihalf.com" <mw@...ihalf.com>
Subject: Re: [PATCH net-next v2] net: mvpp2: Don't use dynamic allocs for
 local variables

Hello Yan,

On Wed, 21 Mar 2018 19:57:47 +0000,
Yan Markman <ymarkman@...vell.com> wrote :

> Hi Maxime

Please avoid top-posting on this list.

> Please check the TWO points:
> 
> 1). The mvpp2_prs_flow_find() returns TID if found
>     The TID=0 is valid FOUND value
>     For Not-found use -ENOENT (just like your mvpp2_prs_vlan_find)

This is actually what is used in this patch. You might be refering to
a previous draft version of this patch.

> 2). The original code always uses "mvpp2_prs_entry *pe" storage
> Zero-Allocated Please check the correctnes of new "mvpp2_prs_entry
> pe" without memset(pe, 0, sizeof(pe));
>    in all procedures where pe=kzalloc() has been replaced

I think we're good on that regard. On places where I didn't memset the
prs_entry, the pe.index field is set, and this is followed by a read
from TCAM that will initialize the prs_entry to the correct value :

		pe.index = tid;
		mvpp2_prs_hw_read(priv, &pe);

> Thanks
> Yan Markman

[...]

Thanks,

Maxime