linux-kernel - Re: [PATCH] net: don't use kvzalloc for DMA memory

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Message-ID: <20180418205539-mutt-send-email-mst@kernel.org>
Date:   Wed, 18 Apr 2018 21:00:23 +0300
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     David Miller <davem@...emloft.net>
Cc:     eric.dumazet@...il.com, mpatocka@...hat.com, edumazet@...gle.com,
        joby.poriyath@...rix.com, bhutchings@...arflare.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        jasowang@...hat.com, virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH] net: don't use kvzalloc for DMA memory

On Wed, Apr 18, 2018 at 01:47:21PM -0400, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@...il.com>
> Date: Wed, 18 Apr 2018 09:51:25 -0700
> 
> > I suggest that virtio_net clearly identifies which part needs a specific allocation
> > and does its itself, instead of abusing the netdev_priv storage.
> > 
> > Ie use a pointer to a block of memory, allocated by virtio_net, for virtio_net.
> 
> +1

I can do this, but just FYI it's all of 16 bytes which is only mapped
for DMA temporarily - and not all of it - a byte here, a byte there.
The amount of hoops one has to jump through just to get 1 byte from
device nowdays is annoying.

-- 
MST