From: Yunsheng Lin <linyunsheng@huawei.com>
To: Mina Almasry <almasrymina@google.com>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<linux-alpha@vger.kernel.org>, <linux-mips@vger.kernel.org>,
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<linux-trace-kernel@vger.kernel.org>,
<linux-arch@vger.kernel.org>, <bpf@vger.kernel.org>,
<linux-kselftest@vger.kernel.org>, <linux-media@vger.kernel.org>,
<dri-devel@lists.freedesktop.org>
Cc: "David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Ivan Kokshaysky" <ink@jurassic.park.msu.ru>,
"Matt Turner" <mattst88@gmail.com>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
"Helge Deller" <deller@gmx.de>,
"Andreas Larsson" <andreas@gaisler.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@kernel.org>,
"Stanislav Fomichev" <sdf@google.com>,
"Hao Luo" <haoluo@google.com>, "Jiri Olsa" <jolsa@kernel.org>,
"David Ahern" <dsahern@kernel.org>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Pavel Begunkov" <asml.silence@gmail.com>,
"David Wei" <dw@davidwei.uk>, "Jason Gunthorpe" <jgg@ziepe.ca>,
"Shailend Chand" <shailend@google.com>,
"Harshitha Ramamurthy" <hramamurthy@google.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Jeroen de Borst" <jeroendb@google.com>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
"Willem de Bruijn" <willemb@google.com>,
"Kaiyuan Zhang" <kaiyuanz@google.com>
Subject: Re: [RFC PATCH net-next v6 05/15] netdev: support binding dma-buf to netdevice
Date: Tue, 5 Mar 2024 20:55:09 +0800 [thread overview]
Message-ID: <da42cea9-c169-599e-f087-d38c419e3dab@huawei.com> (raw)
In-Reply-To: <20240305020153.2787423-6-almasrymina@google.com>
On 2024/3/5 10:01, Mina Almasry wrote:
...
>
> The netdev_dmabuf_binding struct is refcounted, and releases its
> resources only when all the refs are released.
>
> Signed-off-by: Willem de Bruijn <willemb@google.com>
> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
>
> ---
>
> RFC v6:
> - Validate rx queue index
> - Refactor new functions into devmem.c (Pavel)
It seems odd that the functions or stucts in a file called devmem.c
are named after 'dmabuf' instead of 'devmem'.
>
...
> diff --git a/include/net/netmem.h b/include/net/netmem.h
> index d8b810245c1d..72e932a1a948 100644
> --- a/include/net/netmem.h
> +++ b/include/net/netmem.h
> @@ -8,6 +8,16 @@
> #ifndef _NET_NETMEM_H
> #define _NET_NETMEM_H
>
> +#include <net/devmem.h>
> +
> +/* net_iov */
> +
> +struct net_iov {
> + struct dmabuf_genpool_chunk_owner *owner;
> +};
> +
> +/* netmem */
> +
> /**
> * typedef netmem_ref - a nonexistent type marking a reference to generic
> * network memory.
> diff --git a/net/core/Makefile b/net/core/Makefile
> index 821aec06abf1..592f955c1241 100644
> --- a/net/core/Makefile
> +++ b/net/core/Makefile
> @@ -13,7 +13,7 @@ obj-y += dev.o dev_addr_lists.o dst.o netevent.o \
> neighbour.o rtnetlink.o utils.o link_watch.o filter.o \
> sock_diag.o dev_ioctl.o tso.o sock_reuseport.o \
> fib_notifier.o xdp.o flow_offload.o gro.o \
> - netdev-genl.o netdev-genl-gen.o gso.o
> + netdev-genl.o netdev-genl-gen.o gso.o devmem.o
>
> obj-$(CONFIG_NETDEV_ADDR_LIST_TEST) += dev_addr_lists_test.o
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index fe054cbd41e9..bbea1b252529 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -155,6 +155,9 @@
> #include <net/netdev_rx_queue.h>
> #include <net/page_pool/types.h>
> #include <net/page_pool/helpers.h>
> +#include <linux/genalloc.h>
> +#include <linux/dma-buf.h>
> +#include <net/devmem.h>
>
> #include "dev.h"
> #include "net-sysfs.h"
> diff --git a/net/core/devmem.c b/net/core/devmem.c
> new file mode 100644
> index 000000000000..779ad990971e
> --- /dev/null
> +++ b/net/core/devmem.c
> @@ -0,0 +1,293 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Devmem TCP
> + *
> + * Authors: Mina Almasry <almasrymina@google.com>
> + * Willem de Bruijn <willemdebruijn.kernel@gmail.com>
> + * Kaiyuan Zhang <kaiyuanz@google.com
> + */
> +
> +#include <linux/types.h>
> +#include <linux/mm.h>
> +#include <linux/netdevice.h>
> +#include <trace/events/page_pool.h>
> +#include <net/netdev_rx_queue.h>
> +#include <net/page_pool/types.h>
> +#include <net/page_pool/helpers.h>
> +#include <linux/genalloc.h>
> +#include <linux/dma-buf.h>
> +#include <net/devmem.h>
> +
> +/* Device memory support */
> +
> +#ifdef CONFIG_DMA_SHARED_BUFFER
I still think it is worth adding its own config for devmem or dma-buf
for networking, thinking about the embeded system.
> +static void netdev_dmabuf_free_chunk_owner(struct gen_pool *genpool,
> + struct gen_pool_chunk *chunk,
> + void *not_used)
It seems odd to still keep the netdev_ prefix as it is not really related
to netdev, perhaps use 'net_' or something better.
> +{
> + struct dmabuf_genpool_chunk_owner *owner = chunk->owner;
> +
> + kvfree(owner->niovs);
> + kfree(owner);
> +}
> +
> +void __netdev_dmabuf_binding_free(struct netdev_dmabuf_binding *binding)
> +{
> + size_t size, avail;
> +
> + gen_pool_for_each_chunk(binding->chunk_pool,
> + netdev_dmabuf_free_chunk_owner, NULL);
> +
> + size = gen_pool_size(binding->chunk_pool);
> + avail = gen_pool_avail(binding->chunk_pool);
> +
> + if (!WARN(size != avail, "can't destroy genpool. size=%lu, avail=%lu",
> + size, avail))
> + gen_pool_destroy(binding->chunk_pool);
> +
> + dma_buf_unmap_attachment(binding->attachment, binding->sgt,
> + DMA_BIDIRECTIONAL);
For now DMA_FROM_DEVICE seems enough as tx is not supported yet.
> + dma_buf_detach(binding->dmabuf, binding->attachment);
> + dma_buf_put(binding->dmabuf);
> + xa_destroy(&binding->bound_rxq_list);
> + kfree(binding);
> +}
> +
> +static int netdev_restart_rx_queue(struct net_device *dev, int rxq_idx)
> +{
> + void *new_mem;
> + void *old_mem;
> + int err;
> +
> + if (!dev || !dev->netdev_ops)
> + return -EINVAL;
> +
> + if (!dev->netdev_ops->ndo_queue_stop ||
> + !dev->netdev_ops->ndo_queue_mem_free ||
> + !dev->netdev_ops->ndo_queue_mem_alloc ||
> + !dev->netdev_ops->ndo_queue_start)
> + return -EOPNOTSUPP;
> +
> + new_mem = dev->netdev_ops->ndo_queue_mem_alloc(dev, rxq_idx);
> + if (!new_mem)
> + return -ENOMEM;
> +
> + err = dev->netdev_ops->ndo_queue_stop(dev, rxq_idx, &old_mem);
> + if (err)
> + goto err_free_new_mem;
> +
> + err = dev->netdev_ops->ndo_queue_start(dev, rxq_idx, new_mem);
> + if (err)
> + goto err_start_queue;
> +
> + dev->netdev_ops->ndo_queue_mem_free(dev, old_mem);
> +
> + return 0;
> +
> +err_start_queue:
> + dev->netdev_ops->ndo_queue_start(dev, rxq_idx, old_mem);
It might worth mentioning why queue start with old_mem will always
success here as the return value seems to be ignored here.
> +
> +err_free_new_mem:
> + dev->netdev_ops->ndo_queue_mem_free(dev, new_mem);
> +
> + return err;
> +}
> +
> +/* Protected by rtnl_lock() */
> +static DEFINE_XARRAY_FLAGS(netdev_dmabuf_bindings, XA_FLAGS_ALLOC1);
> +
> +void netdev_unbind_dmabuf(struct netdev_dmabuf_binding *binding)
> +{
> + struct netdev_rx_queue *rxq;
> + unsigned long xa_idx;
> + unsigned int rxq_idx;
> +
> + if (!binding)
> + return;
> +
> + if (binding->list.next)
> + list_del(&binding->list);
The above does not seems to be a good pattern to delete a entry, is
there any reason having a checking before the list_del()? seems like
defensive programming?
> +
> + xa_for_each(&binding->bound_rxq_list, xa_idx, rxq) {
> + if (rxq->binding == binding) {
It seems like defensive programming here too?
> + /* We hold the rtnl_lock while binding/unbinding
> + * dma-buf, so we can't race with another thread that
> + * is also modifying this value. However, the driver
> + * may read this config while it's creating its
> + * rx-queues. WRITE_ONCE() here to match the
> + * READ_ONCE() in the driver.
> + */
> + WRITE_ONCE(rxq->binding, NULL);
> +
> + rxq_idx = get_netdev_rx_queue_index(rxq);
> +
> + netdev_restart_rx_queue(binding->dev, rxq_idx);
> + }
> + }
> +
> + xa_erase(&netdev_dmabuf_bindings, binding->id);
> +
> + netdev_dmabuf_binding_put(binding);
> +}
> +
next prev parent reply other threads:[~2024-03-05 12:55 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 2:01 [RFC PATCH net-next v6 00/15] Device Memory TCP Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 01/15] queue_api: define queue api Mina Almasry
2024-03-08 1:30 ` Jakub Kicinski
2024-03-08 2:08 ` Mina Almasry
2024-03-08 3:36 ` Jakub Kicinski
2024-03-08 23:47 ` David Wei
2024-03-09 0:27 ` Mina Almasry
2024-03-11 1:12 ` David Ahern
2024-03-05 2:01 ` [RFC PATCH net-next v6 02/15] net: page_pool: create hooks for custom page providers Mina Almasry
2024-03-05 21:54 ` David Wei
2024-03-05 22:36 ` Mina Almasry
2024-03-06 14:29 ` Pavel Begunkov
2024-03-06 17:04 ` Mina Almasry
2024-03-06 19:12 ` Pavel Begunkov
2024-03-06 21:59 ` Mina Almasry
2024-03-07 14:25 ` Pavel Begunkov
2024-03-08 4:57 ` David Wei
2024-03-08 19:53 ` Mina Almasry
2024-03-18 2:02 ` Christoph Hellwig
2024-03-18 2:49 ` David Wei
2024-03-18 23:22 ` Christoph Hellwig
2024-03-22 17:40 ` Mina Almasry
2024-03-22 23:19 ` Jakub Kicinski
2024-03-24 23:35 ` Christoph Hellwig
2024-03-24 23:35 ` Christoph Hellwig
2024-03-22 17:54 ` Mina Almasry
2024-03-24 23:37 ` Christoph Hellwig
2024-03-26 20:19 ` Mina Almasry
2024-03-28 7:31 ` Christoph Hellwig
2024-04-01 19:22 ` Mina Almasry
2024-04-08 15:34 ` Cong Wang
2024-03-05 2:01 ` [RFC PATCH net-next v6 03/15] net: page_pool: factor out page_pool recycle check Mina Almasry
2024-03-05 12:55 ` Yunsheng Lin
2024-03-05 2:01 ` [RFC PATCH net-next v6 04/15] net: netdev netlink api to bind dma-buf to a net device Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 05/15] netdev: support binding dma-buf to netdevice Mina Almasry
2024-03-05 9:04 ` Arnd Bergmann
2024-03-05 20:00 ` Mina Almasry
2024-03-05 21:42 ` Arnd Bergmann
2024-03-05 12:55 ` Yunsheng Lin [this message]
2024-03-05 21:17 ` Mina Almasry
2024-03-06 12:38 ` Yunsheng Lin
2024-03-06 22:10 ` Mina Almasry
2024-03-07 12:15 ` Yunsheng Lin
2024-03-08 3:58 ` Jakub Kicinski
2024-03-05 2:01 ` [RFC PATCH net-next v6 06/15] netdev: netdevice devmem allocator Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 07/15] page_pool: convert to use netmem Mina Almasry
2024-03-05 21:30 ` Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 08/15] page_pool: devmem support Mina Almasry
2024-03-05 21:42 ` Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 09/15] memory-provider: dmabuf devmem memory provider Mina Almasry
2024-03-06 2:28 ` David Wei
2024-03-06 2:42 ` Mina Almasry
2024-03-06 2:46 ` David Wei
2024-03-06 2:54 ` Mina Almasry
2024-03-06 14:58 ` Pavel Begunkov
2024-03-06 16:51 ` Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 10/15] net: support non paged skb frags Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 11/15] net: add support for skbs with unreadable frags Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 12/15] tcp: RX path for devmem TCP Mina Almasry
2024-03-05 8:41 ` Arnd Bergmann
2024-03-05 19:22 ` Mina Almasry
2024-03-05 19:39 ` Arnd Bergmann
2024-03-05 2:01 ` [RFC PATCH net-next v6 13/15] net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags Mina Almasry
2024-03-05 2:01 ` [RFC PATCH net-next v6 14/15] net: add devmem TCP documentation Mina Almasry
2024-03-08 1:52 ` Jakub Kicinski
2024-03-05 2:01 ` [RFC PATCH net-next v6 15/15] selftests: add ncdevmem, netcat for devmem TCP Mina Almasry
2024-03-05 7:16 ` [RFC PATCH net-next v6 07/15] page_pool: convert to use netmem David Howells
2024-03-05 12:54 ` [RFC PATCH net-next v6 00/15] Device Memory TCP Yunsheng Lin
2024-03-05 19:38 ` Mina Almasry
2024-03-06 12:37 ` Yunsheng Lin
2024-03-26 0:28 ` Mina Almasry
2024-03-26 12:47 ` Yunsheng Lin
2024-03-26 20:14 ` Mina Almasry
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