netdev - Re: [PATCH net-next v5 3/3] tsnep: Add TSN endpoint Ethernet MAC driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANr-f5yiJG_+K63NpSuiAefqM4Cb=UWEdBGKv6mkS5fMZ96new@mail.gmail.com>
Date:   Tue, 16 Nov 2021 22:47:22 +0100
From:   Gerhard Engleder <gerhard@...leder-embedded.com>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, Andrew Lunn <andrew@...n.ch>,
        netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v5 3/3] tsnep: Add TSN endpoint Ethernet MAC driver

On Mon, Nov 15, 2021 at 11:21 PM Heiner Kallweit <hkallweit1@...il.com> wrote:
> On 15.11.2021 21:50, Gerhard Engleder wrote:
> > +     /* entry->properties shall be valid before write pointer is
> > +      * incrememted
> > +      */
> > +     wmb();
>
> A lighter variant like smp_wmb() is not sufficient here?

This is some leftover from lockless descriptor ring processing, which has
been replaced by a spinlock. I will remove it.

> > +             dma_rmb();
> > +
>
> Memory barriers should always have a comment explaining why
> they are needed. I think checkpatch would complain here.

I don't see any checkpatch warning, but you are right. I will document
all DMA memory barriers.

Gerhard