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Message-ID: <20240913150913.1280238-2-sdf@fomichev.me>
Date: Fri, 13 Sep 2024 08:09:10 -0700
From: Stanislav Fomichev <sdf@...ichev.me>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com,
Mina Almasry <almasrymina@...gle.com>
Subject: [RFC PATCH net-next v1 1/4] net: devmem: Implement TX path
Preliminary implementation of the TX path. The API is as follows:
1. bind-tx netlink call to attach dmabuf for TX; queue is not
required, only netdev for dmabuf attachment
2. a set of iovs where iov_base is the offset in the dmabuf and iov_len
is the size of the chunk to send; multiple iovs are supported
3. SCM_DEVMEM_DMABUF cmsg with the dmabuf id from bind-tx
4. MSG_SOCK_DEVMEM sendmsg flag to mirror receive path
In sendmsg, lookup binding by id and refcnt it for every frag in the
skb. None of the drivers are implemented, but skb_frag_dma_unmap
should return proper DMA address. Extra care (TODO) must be taken in the
drivers to not dma_unmap those mappings on completions.
The changes in the kernel/dma/mapping.c are only required to make
devmem work with virtual networking devices (and they expose 1:1
identity mapping) and to enable 'loopback' mode. Loopback mode
lets us test TCP and UAPI paths without having real HW. Not sure
whether it should be a part of a real upstream submission, but it
was useful during the development.
TODO:
- skb_page_unref and __skb_frag_ref seem out of place; unref paths
in general need more care
- potentially something better than tx_iter/tx_vec with its
O(len/PAGE_SIZE) lookups
- move xa_alloc_cyclic to the end
- potentially better separate bind-rx and bind-tx;
direction == DMA_TO_DEVICE feels hacky
- rename skb_add_rx_frag_netmem to skb_add_frag_netmem
Cc: Mina Almasry <almasrymina@...gle.com>
Signed-off-by: Stanislav Fomichev <sdf@...ichev.me>
---
Documentation/netlink/specs/netdev.yaml | 13 +++++
include/linux/skbuff.h | 16 ++++--
include/linux/skbuff_ref.h | 17 ++++++
include/net/devmem.h | 1 +
include/net/sock.h | 1 +
include/uapi/linux/netdev.h | 1 +
kernel/dma/mapping.c | 18 +++++-
net/core/datagram.c | 52 +++++++++++++++++-
net/core/devmem.c | 73 +++++++++++++++++++++++--
net/core/devmem.h | 28 +++++++++-
net/core/netdev-genl-gen.c | 13 +++++
net/core/netdev-genl-gen.h | 1 +
net/core/netdev-genl.c | 65 +++++++++++++++++++++-
net/core/skbuff.c | 21 ++++---
net/core/sock.c | 5 ++
net/ipv4/tcp.c | 38 ++++++++++++-
net/vmw_vsock/virtio_transport_common.c | 2 +-
tools/include/uapi/linux/netdev.h | 1 +
18 files changed, 339 insertions(+), 27 deletions(-)
create mode 120000 include/net/devmem.h
diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 08412c279297..da8e63f45ab9 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -676,6 +676,19 @@ name: netdev
reply:
attributes:
- id
+ -
+ name: bind-tx
+ doc: Bind dmabuf to netdev for TX
+ attribute-set: dmabuf
+ flags: [ admin-perm ]
+ do:
+ request:
+ attributes:
+ - ifindex
+ - fd
+ reply:
+ attributes:
+ - id
kernel-family:
headers: [ "linux/list.h"]
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 39f1d16f3628..eaa4dcee7699 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1702,9 +1702,11 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
+struct net_devmem_dmabuf_binding;
int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, struct iov_iter *from,
- size_t length);
+ size_t length,
+ struct net_devmem_dmabuf_binding *binding);
int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
struct iov_iter *from, size_t length);
@@ -1712,12 +1714,12 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb,
struct msghdr *msg, int len)
{
- return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len);
+ return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len, NULL);
}
int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
- struct msghdr *msg, int len,
- struct ubuf_info *uarg);
+ struct msghdr *msg, int len, struct ubuf_info *uarg,
+ struct net_devmem_dmabuf_binding *binding);
/* Internal */
#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
@@ -3651,6 +3653,12 @@ static inline dma_addr_t skb_frag_dma_map(struct device *dev,
size_t offset, size_t size,
enum dma_data_direction dir)
{
+ struct net_iov *niov;
+
+ if (unlikely(skb_frag_is_net_iov(frag))) {
+ niov = netmem_to_net_iov(frag->netmem);
+ return niov->dma_addr + offset + frag->offset;
+ }
return dma_map_page(dev, skb_frag_page(frag),
skb_frag_off(frag) + offset, size, dir);
}
diff --git a/include/linux/skbuff_ref.h b/include/linux/skbuff_ref.h
index 0f3c58007488..2e621c6572f2 100644
--- a/include/linux/skbuff_ref.h
+++ b/include/linux/skbuff_ref.h
@@ -8,6 +8,7 @@
#define _LINUX_SKBUFF_REF_H
#include <linux/skbuff.h>
+#include <net/devmem.h> /* this is a hack */
/**
* __skb_frag_ref - take an addition reference on a paged fragment.
@@ -17,6 +18,13 @@
*/
static inline void __skb_frag_ref(skb_frag_t *frag)
{
+ if (netmem_is_net_iov(frag->netmem)) {
+ struct net_iov *niov = netmem_to_net_iov(frag->netmem);
+
+ net_devmem_dmabuf_binding_get(niov->owner->binding);
+ return;
+ }
+
get_page(skb_frag_page(frag));
}
@@ -36,6 +44,15 @@ bool napi_pp_put_page(netmem_ref netmem);
static inline void skb_page_unref(netmem_ref netmem, bool recycle)
{
+ /* TODO: find a better place to deref TX binding */
+ if (netmem_is_net_iov(netmem)) {
+ struct net_iov *niov = netmem_to_net_iov(netmem);
+
+ if (niov->owner->binding->tx_vec) {
+ net_devmem_dmabuf_binding_put(niov->owner->binding);
+ return;
+ }
+ }
#ifdef CONFIG_PAGE_POOL
if (recycle && napi_pp_put_page(netmem))
return;
diff --git a/include/net/devmem.h b/include/net/devmem.h
new file mode 120000
index 000000000000..55d6d7361245
--- /dev/null
+++ b/include/net/devmem.h
@@ -0,0 +1 @@
+../../net/core/devmem.h
\ No newline at end of file
diff --git a/include/net/sock.h b/include/net/sock.h
index c58ca8dd561b..964ce7cf9a4f 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1796,6 +1796,7 @@ struct sockcm_cookie {
u64 transmit_time;
u32 mark;
u32 tsflags;
+ u32 devmem_id;
};
static inline void sockcm_init(struct sockcm_cookie *sockc,
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 7c308f04e7a0..56f7b87f8bd0 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -199,6 +199,7 @@ enum {
NETDEV_CMD_NAPI_GET,
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index b1c18058d55f..e7fc06695358 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -183,6 +183,19 @@ void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
}
EXPORT_SYMBOL(dma_unmap_page_attrs);
+static int dma_map_dummy(struct scatterlist *sgl, int nents)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sgl, sg, nents, i) {
+ sg->dma_address = (dma_addr_t)sg_page(sg);
+ sg_dma_len(sg) = sg->length;
+ }
+
+ return nents;
+}
+
static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
@@ -191,8 +204,9 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
BUG_ON(!valid_dma_direction(dir));
- if (WARN_ON_ONCE(!dev->dma_mask))
- return 0;
+ /* TODO: this is here only for loopback mode to have a DMA addr */
+ if (!dev->dma_mask)
+ return dma_map_dummy(sg, nents);
if (dma_map_direct(dev, ops) ||
arch_dma_map_sg_direct(dev, sg, nents))
diff --git a/net/core/datagram.c b/net/core/datagram.c
index f0693707aece..aa352f017634 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -61,6 +61,7 @@
#include <net/tcp_states.h>
#include <trace/events/skb.h>
#include <net/busy_poll.h>
+#include <net/devmem.h> /* this is a hack */
#include <crypto/hash.h>
/*
@@ -692,9 +693,54 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
return 0;
}
+static int zerocopy_fill_skb_from_devmem(struct sk_buff *skb,
+ struct iov_iter *from, int length,
+ struct net_devmem_dmabuf_binding *binding)
+{
+ struct iov_iter niov_iter = binding->tx_iter;
+ int i = skb_shinfo(skb)->nr_frags;
+ struct net_iov *niov;
+ ssize_t prev_off = 0;
+ size_t size;
+
+ while (length && iov_iter_count(from)) {
+ ssize_t delta;
+
+ if (unlikely(i == MAX_SKB_FRAGS))
+ return -EMSGSIZE;
+
+ delta = (ssize_t)iter_iov_addr(from) - prev_off;
+ prev_off = (ssize_t)iter_iov_addr(from);
+
+ if (likely(delta >= 0))
+ iov_iter_advance(&niov_iter, delta);
+ else
+ iov_iter_revert(&niov_iter, -delta);
+
+ size = min_t(size_t, iter_iov_len(from), length);
+ size = min_t(size_t, iter_iov_len(&niov_iter), size);
+ if (!size)
+ return -EFAULT;
+
+ if (!net_devmem_dmabuf_binding_get(binding))
+ return -EFAULT;
+
+ niov = iter_iov(&niov_iter)->iov_base;
+ skb_add_rx_frag_netmem(skb, i, net_iov_to_netmem(niov),
+ niov_iter.iov_offset, size, PAGE_SIZE);
+
+ iov_iter_advance(from, size);
+ length -= size;
+ i++;
+ }
+
+ return 0;
+}
+
int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, struct iov_iter *from,
- size_t length)
+ size_t length,
+ struct net_devmem_dmabuf_binding *binding)
{
unsigned long orig_size = skb->truesize;
unsigned long truesize;
@@ -702,6 +748,8 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
if (msg && msg->msg_ubuf && msg->sg_from_iter)
ret = msg->sg_from_iter(skb, from, length);
+ else if (unlikely(binding))
+ ret = zerocopy_fill_skb_from_devmem(skb, from, length, binding);
else
ret = zerocopy_fill_skb_from_iter(skb, from, length);
@@ -735,7 +783,7 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
if (skb_copy_datagram_from_iter(skb, 0, from, copy))
return -EFAULT;
- return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U);
+ return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U, NULL);
}
EXPORT_SYMBOL(zerocopy_sg_from_iter);
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 11b91c12ee11..f19fdf9634d5 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -23,7 +23,7 @@
/* Device memory support */
-/* Protected by rtnl_lock() */
+static DEFINE_MUTEX(net_devmem_dmabuf_lock);
static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool,
@@ -63,8 +63,10 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
dma_buf_detach(binding->dmabuf, binding->attachment);
dma_buf_put(binding->dmabuf);
xa_destroy(&binding->bound_rxqs);
- kfree(binding);
+ kfree(binding->tx_vec);
+ kfree_rcu(binding, rcu);
}
+EXPORT_SYMBOL(__net_devmem_dmabuf_binding_free);
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
@@ -122,7 +124,9 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
WARN_ON(netdev_rx_queue_restart(binding->dev, rxq_idx));
}
+ mutex_lock(&net_devmem_dmabuf_lock);
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
+ mutex_unlock(&net_devmem_dmabuf_lock);
net_devmem_dmabuf_binding_put(binding);
}
@@ -173,9 +177,10 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
return err;
}
-struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
- struct netlink_ext_ack *extack)
+struct net_devmem_dmabuf_binding *net_devmem_bind_dmabuf(struct net_device *dev,
+ enum dma_data_direction direction,
+ unsigned int dmabuf_fd,
+ struct netlink_ext_ack *extack)
{
struct net_devmem_dmabuf_binding *binding;
static u32 id_alloc_next;
@@ -183,6 +188,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct dma_buf *dmabuf;
unsigned int sg_idx, i;
unsigned long virtual;
+ struct iovec *iov;
int err;
dmabuf = dma_buf_get(dmabuf_fd);
@@ -198,9 +204,14 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
binding->dev = dev;
+ /* TODO: move xa_alloc_cyclic as the last step to make sure binding
+ * lookups get consistent object
+ */
+ mutex_lock(&net_devmem_dmabuf_lock);
err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id,
binding, xa_limit_32b, &id_alloc_next,
GFP_KERNEL);
+ mutex_unlock(&net_devmem_dmabuf_lock);
if (err < 0)
goto err_free_binding;
@@ -218,13 +229,22 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
}
binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment,
- DMA_FROM_DEVICE);
+ direction);
if (IS_ERR(binding->sgt)) {
err = PTR_ERR(binding->sgt);
NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment");
goto err_detach;
}
+ /* dma_buf_map_attachment_unlocked can return non-zero sgt with
+ * zero entries
+ */
+ if (!binding->sgt || binding->sgt->nents == 0) {
+ err = -EINVAL;
+ NL_SET_ERR_MSG(extack, "Empty dmabuf attachment");
+ goto err_detach;
+ }
+
/* For simplicity we expect to make PAGE_SIZE allocations, but the
* binding can be much more flexible than that. We may be able to
* allocate MTU sized chunks here. Leave that for future work...
@@ -236,6 +256,20 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
goto err_unmap;
}
+ if (direction == DMA_TO_DEVICE) {
+ virtual = 0;
+ for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx)
+ virtual += sg_dma_len(sg);
+
+ /* TODO: clearly separate RX and TX paths? */
+ binding->tx_vec =
+ kcalloc(virtual / PAGE_SIZE + 1, sizeof(struct iovec), GFP_KERNEL);
+ if (!binding->tx_vec) {
+ err = -ENOMEM;
+ goto err_unmap;
+ }
+ }
+
virtual = 0;
for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) {
dma_addr_t dma_addr = sg_dma_address(sg);
@@ -277,11 +311,21 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
niov->owner = owner;
page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),
net_devmem_get_dma_addr(niov));
+
+ if (direction == DMA_TO_DEVICE) {
+ iov = &binding->tx_vec[virtual / PAGE_SIZE + i];
+ iov->iov_base = niov;
+ iov->iov_len = PAGE_SIZE;
+ }
}
virtual += len;
}
+ if (direction == DMA_TO_DEVICE)
+ iov_iter_init(&binding->tx_iter, WRITE, binding->tx_vec, virtual / PAGE_SIZE + 1,
+ virtual);
+
return binding;
err_free_chunks:
@@ -294,7 +338,9 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
err_detach:
dma_buf_detach(dmabuf, binding->attachment);
err_free_id:
+ mutex_lock(&net_devmem_dmabuf_lock);
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
+ mutex_unlock(&net_devmem_dmabuf_lock);
err_free_binding:
kfree(binding);
err_put_dmabuf:
@@ -302,6 +348,21 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
return ERR_PTR(err);
}
+struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id)
+{
+ struct net_devmem_dmabuf_binding *binding;
+
+ rcu_read_lock();
+ binding = xa_load(&net_devmem_dmabuf_bindings, id);
+ if (binding) {
+ if (!net_devmem_dmabuf_binding_get(binding))
+ binding = NULL;
+ }
+ rcu_read_unlock();
+
+ return binding;
+}
+
void dev_dmabuf_uninstall(struct net_device *dev)
{
struct net_devmem_dmabuf_binding *binding;
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 76099ef9c482..a3d97fb7d2d2 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -11,6 +11,7 @@
#define _NET_DEVMEM_H
struct netlink_ext_ack;
+#include <linux/dma-direction.h>
struct net_devmem_dmabuf_binding {
struct dma_buf *dmabuf;
@@ -27,9 +28,16 @@ struct net_devmem_dmabuf_binding {
* The binding undos itself and unmaps the underlying dmabuf once all
* those refs are dropped and the binding is no longer desired or in
* use.
+ *
+ * For TX, each skb frag holds a reference.
*/
refcount_t ref;
+ /* XArray lookups happen under RCU lock so we need to keep the dead
+ * bindings around until next grace period.
+ */
+ struct rcu_head rcu;
+
/* The list of bindings currently active. Used for netlink to notify us
* of the user dropping the bind.
*/
@@ -42,6 +50,10 @@ struct net_devmem_dmabuf_binding {
* active.
*/
u32 id;
+
+ /* iov_iter representing all possible net_iov chunks in the dmabuf. */
+ struct iov_iter tx_iter;
+ struct iovec *tx_vec;
};
#if defined(CONFIG_NET_DEVMEM)
@@ -66,8 +78,10 @@ struct dmabuf_genpool_chunk_owner {
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
+net_devmem_bind_dmabuf(struct net_device *dev, enum dma_data_direction direction,
+ unsigned int dmabuf_fd,
struct netlink_ext_ack *extack);
+struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id);
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding);
int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
@@ -104,15 +118,18 @@ static inline u32 net_iov_binding_id(const struct net_iov *niov)
return net_iov_owner(niov)->binding->id;
}
-static inline void
+static inline int
net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding)
{
- refcount_inc(&binding->ref);
+ return refcount_inc_not_zero(&binding->ref);
}
static inline void
net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
{
+ if (!binding)
+ return;
+
if (!refcount_dec_and_test(&binding->ref))
return;
@@ -133,11 +150,16 @@ __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
static inline struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
+ enum dma_data_direction direction,
struct netlink_ext_ack *extack)
{
return ERR_PTR(-EOPNOTSUPP);
}
+static inline struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id)
+{
+ return NULL;
+}
static inline void
net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index b28424ae06d5..db2060f2bcd0 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -87,6 +87,12 @@ static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1]
[NETDEV_A_DMABUF_QUEUES] = NLA_POLICY_NESTED(netdev_queue_id_nl_policy),
};
+/* NETDEV_CMD_BIND_TX - do */
+static const struct nla_policy netdev_bind_tx_nl_policy[NETDEV_A_DMABUF_FD + 1] = {
+ [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
+ [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, },
+};
+
/* Ops table for netdev */
static const struct genl_split_ops netdev_nl_ops[] = {
{
@@ -171,6 +177,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.maxattr = NETDEV_A_DMABUF_FD,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
+ {
+ .cmd = NETDEV_CMD_BIND_TX,
+ .doit = netdev_nl_bind_tx_doit,
+ .policy = netdev_bind_tx_nl_policy,
+ .maxattr = NETDEV_A_DMABUF_FD,
+ .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+ },
};
static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index 8cda334fd042..dc742b6410e9 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -33,6 +33,7 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info);
enum {
NETDEV_NLGRP_MGMT,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 1cb954f2d39e..cd4e4b283ae1 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -780,7 +780,7 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_unlock;
}
- binding = net_devmem_bind_dmabuf(netdev, dmabuf_fd, info->extack);
+ binding = net_devmem_bind_dmabuf(netdev, DMA_FROM_DEVICE, dmabuf_fd, info->extack);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
goto err_unlock;
@@ -837,6 +837,69 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ struct net_devmem_dmabuf_binding *binding;
+ struct list_head *sock_binding_list;
+ struct net_device *netdev;
+ u32 ifindex, dmabuf_fd;
+ struct sk_buff *rsp;
+ int err = 0;
+ void *hdr;
+
+ if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_DEV_IFINDEX) ||
+ GENL_REQ_ATTR_CHECK(info, NETDEV_A_DMABUF_FD))
+ return -EINVAL;
+
+ ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
+ dmabuf_fd = nla_get_u32(info->attrs[NETDEV_A_DMABUF_FD]);
+
+ sock_binding_list =
+ genl_sk_priv_get(&netdev_nl_family, NETLINK_CB(skb).sk);
+ if (IS_ERR(sock_binding_list))
+ return PTR_ERR(sock_binding_list);
+
+ rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!rsp)
+ return -ENOMEM;
+
+ hdr = genlmsg_iput(rsp, info);
+ if (!hdr) {
+ err = -EMSGSIZE;
+ goto err_genlmsg_free;
+ }
+
+ rtnl_lock();
+
+ netdev = __dev_get_by_index(genl_info_net(info), ifindex);
+ if (!netdev || !netif_device_present(netdev)) {
+ err = -ENODEV;
+ goto err_unlock;
+ }
+
+ binding = net_devmem_bind_dmabuf(netdev, DMA_TO_DEVICE, dmabuf_fd, info->extack);
+ if (IS_ERR(binding)) {
+ err = PTR_ERR(binding);
+ goto err_unlock;
+ }
+
+ list_add(&binding->list, sock_binding_list);
+
+ nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
+ genlmsg_end(rsp, hdr);
+
+ rtnl_unlock();
+
+ return genlmsg_reply(rsp, info);
+
+ net_devmem_unbind_dmabuf(binding);
+err_unlock:
+ rtnl_unlock();
+err_genlmsg_free:
+ nlmsg_free(rsp);
+ return err;
+}
+
void netdev_nl_sock_priv_init(struct list_head *priv)
{
INIT_LIST_HEAD(priv);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 74149dc4ee31..7472c16553c6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1021,6 +1021,8 @@ EXPORT_SYMBOL(skb_cow_data_for_xdp);
#if IS_ENABLED(CONFIG_PAGE_POOL)
bool napi_pp_put_page(netmem_ref netmem)
{
+ struct net_iov *niov;
+
netmem = netmem_compound_head(netmem);
/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
@@ -1030,8 +1032,13 @@ bool napi_pp_put_page(netmem_ref netmem)
* and page_is_pfmemalloc() is checked in __page_pool_put_page()
* to avoid recycling the pfmemalloc page.
*/
- if (unlikely(!is_pp_netmem(netmem)))
+ if (unlikely(!is_pp_netmem(netmem))) {
+ /* avoid triggering WARN_ON's for loopback mode */
+ niov = netmem_to_net_iov(netmem);
+ if (niov && niov->owner && niov->owner->binding->tx_vec)
+ return true;
return false;
+ }
page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, false);
@@ -1880,8 +1887,8 @@ const struct ubuf_info_ops msg_zerocopy_ubuf_ops = {
EXPORT_SYMBOL_GPL(msg_zerocopy_ubuf_ops);
int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
- struct msghdr *msg, int len,
- struct ubuf_info *uarg)
+ struct msghdr *msg, int len, struct ubuf_info *uarg,
+ struct net_devmem_dmabuf_binding *binding)
{
int err, orig_len = skb->len;
@@ -1900,7 +1907,7 @@ int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
return -EEXIST;
}
- err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len);
+ err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len, binding);
if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
struct sock *save_sk = skb->sk;
@@ -1969,12 +1976,12 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
int i, order, psize, new_frags;
u32 d_off;
+ if (!skb_frags_readable(skb))
+ return 0;
+
if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
return -EINVAL;
- if (!skb_frags_readable(skb))
- return -EFAULT;
-
if (!num_frags)
goto release;
diff --git a/net/core/sock.c b/net/core/sock.c
index bbb57b5af0b1..195ce15ab047 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2931,6 +2931,11 @@ int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
case SCM_RIGHTS:
case SCM_CREDENTIALS:
break;
+ case SCM_DEVMEM_DMABUF:
+ if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
+ return -EINVAL;
+ sockc->devmem_id = *(u32 *)CMSG_DATA(cmsg);
+ break;
default:
return -EINVAL;
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4f77bd862e95..d48c30a7ef36 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1050,6 +1050,7 @@ int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied,
int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
{
+ struct net_devmem_dmabuf_binding *binding = NULL;
struct tcp_sock *tp = tcp_sk(sk);
struct ubuf_info *uarg = NULL;
struct sk_buff *skb;
@@ -1079,6 +1080,21 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
else
uarg_to_msgzc(uarg)->zerocopy = 0;
}
+ } else if (flags & MSG_SOCK_DEVMEM) {
+ if (!(sk->sk_route_caps & NETIF_F_SG) || msg->msg_ubuf ||
+ !sock_flag(sk, SOCK_ZEROCOPY)) {
+ err = -EINVAL;
+ goto out_err;
+ }
+
+ skb = tcp_write_queue_tail(sk);
+ uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb));
+ if (!uarg) {
+ err = -ENOBUFS;
+ goto out_err;
+ }
+
+ zc = MSG_ZEROCOPY;
} else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
if (sk->sk_route_caps & NETIF_F_SG)
zc = MSG_SPLICE_PAGES;
@@ -1131,6 +1147,24 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
}
}
+ if (unlikely(flags & MSG_SOCK_DEVMEM)) {
+ if (sockc.devmem_id == 0) {
+ err = -EINVAL;
+ goto out_err;
+ }
+
+ binding = net_devmem_lookup_dmabuf(sockc.devmem_id);
+ if (!binding || !binding->tx_vec) {
+ err = -EINVAL;
+ goto out_err;
+ }
+
+ if (sock_net(sk) != dev_net(binding->dev)) {
+ err = -EINVAL;
+ goto out_err;
+ }
+ }
+
/* This should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
@@ -1247,7 +1281,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto wait_for_space;
}
- err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
+ err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg, binding);
if (err == -EMSGSIZE || err == -EEXIST) {
tcp_mark_push(tp, skb);
goto new_segment;
@@ -1328,6 +1362,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
if (uarg && !msg->msg_ubuf)
net_zcopy_put(uarg);
+ net_devmem_dmabuf_binding_put(binding);
return copied + copied_syn;
do_error:
@@ -1345,6 +1380,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
sk->sk_write_space(sk);
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
+ net_devmem_dmabuf_binding_put(binding);
return err;
}
EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 884ee128851e..d6942111645a 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -105,7 +105,7 @@ static int virtio_transport_fill_skb(struct sk_buff *skb,
if (zcopy)
return __zerocopy_sg_from_iter(info->msg, NULL, skb,
&info->msg->msg_iter,
- len);
+ len, NULL);
return memcpy_from_msg(skb_put(skb, len), info->msg, len);
}
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 7c308f04e7a0..56f7b87f8bd0 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -199,6 +199,7 @@ enum {
NETDEV_CMD_NAPI_GET,
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
--
2.46.0
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