From: "Michael S. Tsirkin" <mst@redhat.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Christoph Hellwig <hch@infradead.org>,
virtualization@lists.linux-foundation.org,
Jason Wang <jasowang@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH vhost v11 05/10] virtio_ring: introduce virtqueue_dma_dev()
Date: Mon, 24 Jul 2023 16:05:50 -0400 [thread overview]
Message-ID: <20230724160511-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <1689838441.2670174-9-xuanzhuo@linux.alibaba.com>
On Thu, Jul 20, 2023 at 03:34:01PM +0800, Xuan Zhuo wrote:
> On Wed, 19 Jul 2023 23:57:51 -0700, Christoph Hellwig <hch@infradead.org> wrote:
> > On Thu, Jul 20, 2023 at 02:45:14PM +0800, Xuan Zhuo wrote:
> > > virtqueue_dma_dev() return the device that working with the DMA APIs.
> > > Then that can be used like other devices. So what is the problem.
> > >
> > > I always think the code path without the DMA APIs is the trouble for you.
> >
> > Because we now have an API where the upper level drivers sometimes
> > see the dma device and sometimes not.
>
> No dma device is just for the old devices.
>
> The API without DMA dev are only compatible with older devices. We can't give up
> these old devices, but we also have to embrace new features.
>
> > This will be abused and cause
> > trouble sooner than you can say "layering".
>
> I don't understand what the possible trouble here is.
>
> When no dma device, the driver just does the same thing as before.
>
> Thanks.
Instead of skipping operations, Christoph wants wrappers that
do nothing for non dma case.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
netdev@vger.kernel.org, John Fastabend <john.fastabend@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
virtualization@lists.linux-foundation.org,
Christoph Hellwig <hch@infradead.org>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
bpf@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH vhost v11 05/10] virtio_ring: introduce virtqueue_dma_dev()
Date: Mon, 24 Jul 2023 16:05:50 -0400 [thread overview]
Message-ID: <20230724160511-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <1689838441.2670174-9-xuanzhuo@linux.alibaba.com>
On Thu, Jul 20, 2023 at 03:34:01PM +0800, Xuan Zhuo wrote:
> On Wed, 19 Jul 2023 23:57:51 -0700, Christoph Hellwig <hch@infradead.org> wrote:
> > On Thu, Jul 20, 2023 at 02:45:14PM +0800, Xuan Zhuo wrote:
> > > virtqueue_dma_dev() return the device that working with the DMA APIs.
> > > Then that can be used like other devices. So what is the problem.
> > >
> > > I always think the code path without the DMA APIs is the trouble for you.
> >
> > Because we now have an API where the upper level drivers sometimes
> > see the dma device and sometimes not.
>
> No dma device is just for the old devices.
>
> The API without DMA dev are only compatible with older devices. We can't give up
> these old devices, but we also have to embrace new features.
>
> > This will be abused and cause
> > trouble sooner than you can say "layering".
>
> I don't understand what the possible trouble here is.
>
> When no dma device, the driver just does the same thing as before.
>
> Thanks.
Instead of skipping operations, Christoph wants wrappers that
do nothing for non dma case.
--
MST
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next prev parent reply other threads:[~2023-07-24 20:05 UTC|newest]
Thread overview: 176+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-10 3:42 [PATCH vhost v11 00/10] virtio core prepares for AF_XDP Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 01/10] virtio_ring: check use_dma_api before unmap desc for indirect Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 02/10] virtio_ring: put mapping error check in vring_map_one_sg Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 03/10] virtio_ring: introduce virtqueue_set_premapped() Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-12 8:24 ` Jason Wang
2023-07-12 8:35 ` Xuan Zhuo
2023-07-12 8:35 ` Xuan Zhuo
2023-07-13 11:14 ` Christoph Hellwig
2023-07-13 11:14 ` Christoph Hellwig
2023-07-13 14:47 ` Michael S. Tsirkin
2023-07-13 14:47 ` Michael S. Tsirkin
2023-07-20 6:22 ` Christoph Hellwig
2023-07-20 6:22 ` Christoph Hellwig
2023-07-13 14:52 ` Michael S. Tsirkin
2023-07-13 14:52 ` Michael S. Tsirkin
2023-07-10 3:42 ` [PATCH vhost v11 04/10] virtio_ring: support add premapped buf Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-12 8:31 ` Jason Wang
2023-07-12 8:31 ` Jason Wang
2023-07-12 8:33 ` Xuan Zhuo
2023-07-12 8:33 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 05/10] virtio_ring: introduce virtqueue_dma_dev() Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-12 8:33 ` Jason Wang
2023-07-12 8:33 ` Jason Wang
2023-07-13 11:15 ` Christoph Hellwig
2023-07-13 11:15 ` Christoph Hellwig
2023-07-13 14:51 ` Michael S. Tsirkin
2023-07-13 14:51 ` Michael S. Tsirkin
2023-07-20 6:22 ` Christoph Hellwig
2023-07-20 6:22 ` Christoph Hellwig
2023-07-20 6:45 ` Xuan Zhuo
2023-07-20 6:45 ` Xuan Zhuo
2023-07-20 6:57 ` Christoph Hellwig
2023-07-20 6:57 ` Christoph Hellwig
2023-07-20 7:34 ` Xuan Zhuo
2023-07-20 7:34 ` Xuan Zhuo
2023-07-24 20:05 ` Michael S. Tsirkin [this message]
2023-07-24 20:05 ` Michael S. Tsirkin
2023-07-20 17:21 ` Michael S. Tsirkin
2023-07-20 17:21 ` Michael S. Tsirkin
2023-07-24 16:43 ` Christoph Hellwig
2023-07-24 16:43 ` Christoph Hellwig
2023-07-25 2:13 ` Xuan Zhuo
2023-07-25 2:13 ` Xuan Zhuo
2023-07-25 7:34 ` Michael S. Tsirkin
2023-07-25 7:34 ` Michael S. Tsirkin
2023-07-25 11:07 ` Xuan Zhuo
2023-07-25 11:07 ` Xuan Zhuo
2023-07-28 6:02 ` Xuan Zhuo
2023-07-28 6:02 ` Xuan Zhuo
2023-07-28 15:03 ` Jakub Kicinski
2023-07-31 1:23 ` Jason Wang
2023-07-31 1:23 ` Jason Wang
2023-07-31 15:46 ` Jakub Kicinski
2023-08-01 2:03 ` Xuan Zhuo
2023-08-01 2:03 ` Xuan Zhuo
2023-08-01 2:36 ` Jakub Kicinski
2023-08-01 2:57 ` Xuan Zhuo
2023-08-01 2:57 ` Xuan Zhuo
2023-08-01 15:45 ` Jakub Kicinski
2023-08-02 1:36 ` Xuan Zhuo
2023-08-02 1:36 ` Xuan Zhuo
2023-08-02 11:12 ` Pavel Begunkov
2023-07-31 2:34 ` Xuan Zhuo
2023-07-31 2:34 ` Xuan Zhuo
2023-08-01 16:17 ` Michael S. Tsirkin
2023-08-01 16:17 ` Michael S. Tsirkin
2023-08-02 1:49 ` Xuan Zhuo
2023-08-02 1:49 ` Xuan Zhuo
2023-08-07 6:14 ` Xuan Zhuo
2023-08-07 6:14 ` Xuan Zhuo
2023-08-08 2:26 ` Jason Wang
2023-08-08 2:26 ` Jason Wang
2023-08-08 2:47 ` Xuan Zhuo
2023-08-08 2:47 ` Xuan Zhuo
2023-08-08 3:08 ` Jason Wang
2023-08-08 3:08 ` Jason Wang
2023-08-08 3:09 ` Xuan Zhuo
2023-08-08 3:09 ` Xuan Zhuo
2023-08-08 3:49 ` Jason Wang
2023-08-08 3:49 ` Jason Wang
2023-08-08 3:54 ` Xuan Zhuo
2023-08-08 3:59 ` Jason Wang
2023-08-08 3:59 ` Jason Wang
2023-08-08 4:07 ` Xuan Zhuo
2023-08-10 1:56 ` Xuan Zhuo
2023-08-10 1:56 ` Xuan Zhuo
2023-08-10 6:37 ` Jason Wang
2023-08-10 6:37 ` Jason Wang
2023-08-10 6:40 ` Michael S. Tsirkin
2023-08-10 6:40 ` Michael S. Tsirkin
2023-08-10 6:39 ` Michael S. Tsirkin
2023-08-10 6:39 ` Michael S. Tsirkin
2023-08-10 6:47 ` Xuan Zhuo
2023-08-10 6:47 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 06/10] virtio_ring: skip unmap for premapped Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-13 3:50 ` Jason Wang
2023-07-13 3:50 ` Jason Wang
2023-07-13 4:02 ` Xuan Zhuo
2023-07-13 4:02 ` Xuan Zhuo
2023-07-13 4:21 ` Jason Wang
2023-07-13 4:21 ` Jason Wang
2023-07-13 5:45 ` Xuan Zhuo
2023-07-13 5:45 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 07/10] virtio_ring: correct the expression of the description of virtqueue_resize() Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 08/10] virtio_ring: separate the logic of reset/enable from virtqueue_resize Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 09/10] virtio_ring: introduce virtqueue_reset() Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 3:42 ` [PATCH vhost v11 10/10] virtio_net: merge dma operation for one page Xuan Zhuo
2023-07-10 3:42 ` Xuan Zhuo
2023-07-10 9:40 ` Michael S. Tsirkin
2023-07-10 9:40 ` Michael S. Tsirkin
2023-07-10 10:18 ` Xuan Zhuo
2023-07-10 10:18 ` Xuan Zhuo
2023-07-10 11:59 ` Michael S. Tsirkin
2023-07-10 11:59 ` Michael S. Tsirkin
2023-07-10 12:38 ` Xuan Zhuo
2023-07-10 12:38 ` Xuan Zhuo
2023-07-11 2:36 ` Jason Wang
2023-07-11 2:36 ` Jason Wang
2023-07-11 2:40 ` Xuan Zhuo
2023-07-11 2:40 ` Xuan Zhuo
2023-07-11 2:58 ` Jason Wang
2023-07-11 2:58 ` Jason Wang
2023-07-12 7:54 ` Xuan Zhuo
2023-07-12 7:54 ` Xuan Zhuo
2023-07-12 8:32 ` Xuan Zhuo
2023-07-12 8:32 ` Xuan Zhuo
2023-07-12 8:37 ` Jason Wang
2023-07-12 8:37 ` Jason Wang
2023-07-12 8:38 ` Xuan Zhuo
2023-07-12 8:38 ` Xuan Zhuo
2023-07-14 10:37 ` Michael S. Tsirkin
2023-07-14 10:37 ` Michael S. Tsirkin
2023-07-19 3:21 ` Xuan Zhuo
2023-07-19 3:21 ` Xuan Zhuo
2023-07-19 8:55 ` Michael S. Tsirkin
2023-07-19 8:55 ` Michael S. Tsirkin
2023-07-19 9:38 ` Jason Wang
2023-07-19 9:38 ` Jason Wang
2023-07-19 9:51 ` Michael S. Tsirkin
2023-07-19 9:51 ` Michael S. Tsirkin
2023-07-20 2:26 ` Xuan Zhuo
2023-07-20 2:26 ` Xuan Zhuo
2023-07-20 2:24 ` Xuan Zhuo
2023-07-20 2:24 ` Xuan Zhuo
2023-07-13 4:20 ` Jason Wang
2023-07-13 4:20 ` Jason Wang
2023-07-13 5:53 ` Xuan Zhuo
2023-07-13 5:53 ` Xuan Zhuo
2023-07-13 6:51 ` Xuan Zhuo
2023-07-13 6:51 ` Xuan Zhuo
2023-07-14 3:56 ` Jason Wang
2023-07-14 3:56 ` Jason Wang
2023-07-20 6:23 ` Christoph Hellwig
2023-07-20 6:23 ` Christoph Hellwig
2023-07-20 7:41 ` Jason Wang
2023-07-20 7:41 ` Jason Wang
2023-07-20 8:21 ` Christoph Hellwig
2023-07-20 8:21 ` Christoph Hellwig
2023-07-13 7:00 ` Xuan Zhuo
2023-07-13 7:00 ` Xuan Zhuo
2023-07-14 3:57 ` Jason Wang
2023-07-14 3:57 ` Jason Wang
2023-07-14 3:58 ` Xuan Zhuo
2023-07-14 3:58 ` Xuan Zhuo
2023-07-14 5:45 ` Jason Wang
2023-07-14 5:45 ` Jason Wang
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