Re: [PATCH v4 1/6] virtio-net: Stop doing DMA from the stack

On Fri, Oct 30, 2015 at 6:55 AM, Christian Borntraeger
[off-list ref] wrote:

Am 30.10.2015 um 02:09 schrieb Andy Lutomirski:

quoted

From: "Michael S. Tsirkin" <mst@redhat.com>

Once virtio starts using the DMA API, we won't be able to safely DMA
from the stack.  virtio-net does a couple of config DMA requests
from small stack buffers -- switch to using dynamically-allocated
memory.

This should have no effect on any performance-critical code paths.

[I wrote the subject and commit message.  mst wrote the code. --luto]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
signed-off-by: Michael S. Tsirkin <mst@redhat.com>

I still get an error when using multiqueue:

#  ethtool -L eth0 combined 4
[   33.534686] virtio_ccw 0.0.000d: DMA-API: device driver maps memory from stack [addr=00000000629e7c06]

Fixed in my branch, I think.

--Andy