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net: devmem: Implement TX path

Browse source 
Augment dmabuf binding to be able to handle TX. Additional to all the RX
binding, we also create tx_vec needed for the TX path.

Provide API for sendmsg to be able to send dmabufs bound to this device:

- Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from.
- MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf.

Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY
implementation, while disabling instances where MSG_ZEROCOPY falls back
to copying.

We additionally pipe the binding down to the new
zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems
instead of the traditional page netmems.

We also special case skb_frag_dma_map to return the dma-address of these
dmabuf net_iovs instead of attempting to map pages.

The TX path may release the dmabuf in a context where we cannot wait.
This happens when the user unbinds a TX dmabuf while there are still
references to its netmems in the TX path. In that case, the netmems will
be put_netmem'd from a context where we can't unmap the dmabuf, Resolve
this by making __net_devmem_dmabuf_binding_free schedule_work'd.

Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat
of the implementation came from devmem TCP RFC v1[1], which included the
TX path, but Stan did all the rebasing on top of netmem/net_iov.

Cc: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250508004830.4100853-5-almasrymina@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Mina Almasry 2025-05-08 00:48:24 +00:00 • committed by Paolo Abeni
parent 8802087d20
commit bd61848900
13 changed files with 340 additions and 60 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
include/linux/skbuff.h
View file

@ -1707,13 +1707,16 @@ static inline void skb_set_end_offset(struct sk_buff *skb, unsigned int offset)
extern const struct ubuf_info_ops msg_zerocopy_ubuf_ops;
struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
struct ubuf_info *uarg);
struct ubuf_info *uarg, bool devmem);
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);
@ -1721,12 +1724,14 @@ 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 ubuf_info *uarg,
struct net_devmem_dmabuf_binding *binding);
/* Internal */
#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
@ -3697,6 +3702,10 @@ static inline dma_addr_t __skb_frag_dma_map(struct device *dev,
size_t offset, size_t size,
enum dma_data_direction dir)
{
if (skb_frag_is_net_iov(frag)) {
return netmem_to_net_iov(frag->netmem)->dma_addr + offset +
frag->offset;
}
return dma_map_page(dev, skb_frag_page(frag),
skb_frag_off(frag) + offset, size, dir);
}

1
include/net/sock.h
View file

@ -1851,6 +1851,7 @@ struct sockcm_cookie {
u32 tsflags;
u32 ts_opt_id;
u32 priority;
u32 dmabuf_id;
};
static inline void sockcm_init(struct sockcm_cookie *sockc,

2
io_uring/zcrx.c
View file

@ -810,7 +810,7 @@ static int io_zcrx_recv_frag(struct io_kiocb *req, struct io_zcrx_ifq *ifq,
return io_zcrx_copy_frag(req, ifq, frag, off, len);
niov = netmem_to_net_iov(frag->netmem);
if (niov->pp->mp_ops != &io_uring_pp_zc_ops ||
if (!niov->pp || niov->pp->mp_ops != &io_uring_pp_zc_ops ||
io_pp_to_ifq(niov->pp) != ifq)
return -EFAULT;

48
net/core/datagram.c
View file

@ -63,6 +63,8 @@
#include <net/busy_poll.h>
#include <crypto/hash.h>
#include "devmem.h"
/*
* Is a socket 'connection oriented' ?
*/
@ -691,9 +693,49 @@ 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)
{
int i = skb_shinfo(skb)->nr_frags;
size_t virt_addr, size, off;
struct net_iov *niov;
/* Devmem filling works by taking an IOVEC from the user where the
* iov_addrs are interpreted as an offset in bytes into the dma-buf to
* send from. We do not support other iter types.
*/
if (iov_iter_type(from) != ITER_IOVEC)
return -EFAULT;
while (length && iov_iter_count(from)) {
if (i == MAX_SKB_FRAGS)
return -EMSGSIZE;
virt_addr = (size_t)iter_iov_addr(from);
niov = net_devmem_get_niov_at(binding, virt_addr, &off, &size);
if (!niov)
return -EFAULT;
size = min_t(size_t, size, length);
size = min_t(size_t, size, iter_iov_len(from));
get_netmem(net_iov_to_netmem(niov));
skb_add_rx_frag_netmem(skb, i, net_iov_to_netmem(niov), off,
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;
@ -701,6 +743,8 @@ 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 (binding)
ret = zerocopy_fill_skb_from_devmem(skb, from, length, binding);
else
ret = zerocopy_fill_skb_from_iter(skb, from, length);
@ -734,7 +778,7 @@ 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);

118
net/core/devmem.c
View file

@ -16,6 +16,7 @@
#include <net/netdev_rx_queue.h>
#include <net/page_pool/helpers.h>
#include <net/page_pool/memory_provider.h>
#include <net/sock.h>
#include <trace/events/page_pool.h>
#include "devmem.h"
@ -52,8 +53,10 @@ static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov)
((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);
}
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
void __net_devmem_dmabuf_binding_free(struct work_struct *wq)
{
struct net_devmem_dmabuf_binding *binding = container_of(wq, typeof(*binding), unbind_w);
size_t size, avail;
gen_pool_for_each_chunk(binding->chunk_pool,
@ -71,8 +74,10 @@ 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);
kvfree(binding->tx_vec);
kfree(binding);
}
EXPORT_SYMBOL(__net_devmem_dmabuf_binding_free);
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
@ -117,6 +122,13 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
unsigned long xa_idx;
unsigned int rxq_idx;
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
/* Ensure no tx net_devmem_lookup_dmabuf() are in flight after the
* erase.
*/
synchronize_net();
if (binding->list.next)
list_del(&binding->list);
@ -131,8 +143,6 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
__net_mp_close_rxq(binding->dev, rxq_idx, &mp_params);
}
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
net_devmem_dmabuf_binding_put(binding);
}
@ -166,8 +176,9 @@ err_close_rxq:
}
struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct netlink_ext_ack *extack)
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;
@ -189,13 +200,6 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
}
binding->dev = dev;
err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id,
binding, xa_limit_32b, &id_alloc_next,
GFP_KERNEL);
if (err < 0)
goto err_free_binding;
xa_init_flags(&binding->bound_rxqs, XA_FLAGS_ALLOC);
refcount_set(&binding->ref, 1);
@ -206,26 +210,36 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
if (IS_ERR(binding->attachment)) {
err = PTR_ERR(binding->attachment);
NL_SET_ERR_MSG(extack, "Failed to bind dmabuf to device");
goto err_free_id;
goto err_free_binding;
}
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;
}
if (direction == DMA_TO_DEVICE) {
binding->tx_vec = kvmalloc_array(dmabuf->size / PAGE_SIZE,
sizeof(struct net_iov *),
GFP_KERNEL);
if (!binding->tx_vec) {
err = -ENOMEM;
goto err_unmap;
}
}
/* 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...
*/
binding->chunk_pool =
gen_pool_create(PAGE_SHIFT, dev_to_node(&dev->dev));
binding->chunk_pool = gen_pool_create(PAGE_SHIFT,
dev_to_node(&dev->dev));
if (!binding->chunk_pool) {
err = -ENOMEM;
goto err_unmap;
goto err_tx_vec;
}
virtual = 0;
@ -270,24 +284,32 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
niov->owner = &owner->area;
page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),
net_devmem_get_dma_addr(niov));
if (direction == DMA_TO_DEVICE)
binding->tx_vec[owner->area.base_virtual / PAGE_SIZE + i] = niov;
}
virtual += len;
}
err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id,
binding, xa_limit_32b, &id_alloc_next,
GFP_KERNEL);
if (err < 0)
goto err_free_chunks;
return binding;
err_free_chunks:
gen_pool_for_each_chunk(binding->chunk_pool,
net_devmem_dmabuf_free_chunk_owner, NULL);
gen_pool_destroy(binding->chunk_pool);
err_tx_vec:
kvfree(binding->tx_vec);
err_unmap:
dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt,
DMA_FROM_DEVICE);
err_detach:
dma_buf_detach(dmabuf, binding->attachment);
err_free_id:
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
err_free_binding:
kfree(binding);
err_put_dmabuf:
@ -295,6 +317,21 @@ err_put_dmabuf:
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 net_devmem_get_net_iov(struct net_iov *niov)
{
net_devmem_dmabuf_binding_get(net_devmem_iov_binding(niov));
@ -305,6 +342,49 @@ void net_devmem_put_net_iov(struct net_iov *niov)
net_devmem_dmabuf_binding_put(net_devmem_iov_binding(niov));
}
struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk,
unsigned int dmabuf_id)
{
struct net_devmem_dmabuf_binding *binding;
struct dst_entry *dst = __sk_dst_get(sk);
int err = 0;
binding = net_devmem_lookup_dmabuf(dmabuf_id);
if (!binding || !binding->tx_vec) {
err = -EINVAL;
goto out_err;
}
/* The dma-addrs in this binding are only reachable to the corresponding
* net_device.
*/
if (!dst || !dst->dev || dst->dev->ifindex != binding->dev->ifindex) {
err = -ENODEV;
goto out_err;
}
return binding;
out_err:
if (binding)
net_devmem_dmabuf_binding_put(binding);
return ERR_PTR(err);
}
struct net_iov *
net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding,
size_t virt_addr, size_t *off, size_t *size)
{
if (virt_addr >= binding->dmabuf->size)
return NULL;
*off = virt_addr % PAGE_SIZE;
*size = PAGE_SIZE - *off;
return binding->tx_vec[virt_addr / PAGE_SIZE];
}
/*** "Dmabuf devmem memory provider" ***/
int mp_dmabuf_devmem_init(struct page_pool *pool)

61
net/core/devmem.h
View file

@ -23,8 +23,9 @@ struct net_devmem_dmabuf_binding {
/* The user holds a ref (via the netlink API) for as long as they want
* the binding to remain alive. Each page pool using this binding holds
* a ref to keep the binding alive. Each allocated net_iov holds a
* ref.
* a ref to keep the binding alive. The page_pool does not release the
* ref until all the net_iovs allocated from this binding are released
* back to the page_pool.
*
* The binding undos itself and unmaps the underlying dmabuf once all
* those refs are dropped and the binding is no longer desired or in
@ -32,7 +33,10 @@ struct net_devmem_dmabuf_binding {
*
* net_devmem_get_net_iov() on dmabuf net_iovs will increment this
* reference, making sure that the binding remains alive until all the
* net_iovs are no longer used.
* net_iovs are no longer used. net_iovs allocated from this binding
* that are stuck in the TX path for any reason (such as awaiting
* retransmits) hold a reference to the binding until the skb holding
* them is freed.
*/
refcount_t ref;
@ -48,6 +52,14 @@ struct net_devmem_dmabuf_binding {
* active.
*/
u32 id;
/* Array of net_iov pointers for this binding, sorted by virtual
* address. This array is convenient to map the virtual addresses to
* net_iovs in the TX path.
*/
struct net_iov **tx_vec;
struct work_struct unbind_w;
};
#if defined(CONFIG_NET_DEVMEM)
@ -64,14 +76,17 @@ struct dmabuf_genpool_chunk_owner {
dma_addr_t base_dma_addr;
};
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
void __net_devmem_dmabuf_binding_free(struct work_struct *wq);
struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct netlink_ext_ack *extack);
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,
struct netlink_ext_ack *extack);
void net_devmem_bind_tx_release(struct sock *sk);
static inline struct dmabuf_genpool_chunk_owner *
net_devmem_iov_to_chunk_owner(const struct net_iov *niov)
@ -100,10 +115,10 @@ static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov)
((unsigned long)net_iov_idx(niov) << PAGE_SHIFT);
}
static inline void
static inline bool
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
@ -112,7 +127,8 @@ net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
if (!refcount_dec_and_test(&binding->ref))
return;
__net_devmem_dmabuf_binding_free(binding);
INIT_WORK(&binding->unbind_w, __net_devmem_dmabuf_binding_free);
schedule_work(&binding->unbind_w);
}
void net_devmem_get_net_iov(struct net_iov *niov);
@ -123,6 +139,11 @@ net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
void net_devmem_free_dmabuf(struct net_iov *ppiov);
bool net_is_devmem_iov(struct net_iov *niov);
struct net_devmem_dmabuf_binding *
net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id);
struct net_iov *
net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr,
size_t *off, size_t *size);
#else
struct net_devmem_dmabuf_binding;
@ -140,18 +161,23 @@ static inline void net_devmem_put_net_iov(struct net_iov *niov)
{
}
static inline void
__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
static inline void __net_devmem_dmabuf_binding_free(struct work_struct *wq)
{
}
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)
{
@ -190,6 +216,19 @@ static inline bool net_is_devmem_iov(struct net_iov *niov)
{
return false;
}
static inline struct net_devmem_dmabuf_binding *
net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline struct net_iov *
net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr,
size_t *off, size_t *size)
{
return NULL;
}
#endif
#endif /* _NET_DEVMEM_H */

71
net/core/netdev-genl.c
View file

@ -907,7 +907,8 @@ 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;
@ -968,10 +969,74 @@ err_genlmsg_free:
return err;
}
/* stub */
int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
{
return 0;
struct net_devmem_dmabuf_binding *binding;
struct netdev_nl_sock *priv;
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]);
priv = genl_sk_priv_get(&netdev_nl_family, NETLINK_CB(skb).sk);
if (IS_ERR(priv))
return PTR_ERR(priv);
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;
}
mutex_lock(&priv->lock);
netdev = netdev_get_by_index_lock(genl_info_net(info), ifindex);
if (!netdev) {
err = -ENODEV;
goto err_unlock_sock;
}
if (!netif_device_present(netdev)) {
err = -ENODEV;
goto err_unlock_netdev;
}
binding = net_devmem_bind_dmabuf(netdev, DMA_TO_DEVICE, dmabuf_fd,
info->extack);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
goto err_unlock_netdev;
}
list_add(&binding->list, &priv->bindings);
nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
genlmsg_end(rsp, hdr);
netdev_unlock(netdev);
mutex_unlock(&priv->lock);
return genlmsg_reply(rsp, info);
err_unlock_netdev:
netdev_unlock(netdev);
err_unlock_sock:
mutex_unlock(&priv->lock);
err_genlmsg_free:
nlmsg_free(rsp);
return err;
}
void netdev_nl_sock_priv_init(struct netdev_nl_sock *priv)

18
net/core/skbuff.c
View file

@ -1655,7 +1655,8 @@ void mm_unaccount_pinned_pages(struct mmpin *mmp)
}
EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size)
static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size,
bool devmem)
{
struct ubuf_info_msgzc *uarg;
struct sk_buff *skb;
@ -1670,7 +1671,7 @@ static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size)
uarg = (void *)skb->cb;
uarg->mmp.user = NULL;
if (mm_account_pinned_pages(&uarg->mmp, size)) {
if (likely(!devmem) && mm_account_pinned_pages(&uarg->mmp, size)) {
kfree_skb(skb);
return NULL;
}
@ -1693,7 +1694,7 @@ static inline struct sk_buff *skb_from_uarg(struct ubuf_info_msgzc *uarg)
}
struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
struct ubuf_info *uarg)
struct ubuf_info *uarg, bool devmem)
{
if (uarg) {
struct ubuf_info_msgzc *uarg_zc;
@ -1723,7 +1724,8 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
next = (u32)atomic_read(&sk->sk_zckey);
if ((u32)(uarg_zc->id + uarg_zc->len) == next) {
if (mm_account_pinned_pages(&uarg_zc->mmp, size))
if (likely(!devmem) &&
mm_account_pinned_pages(&uarg_zc->mmp, size))
return NULL;
uarg_zc->len++;
uarg_zc->bytelen = bytelen;
@ -1738,7 +1740,7 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
}
new_alloc:
return msg_zerocopy_alloc(sk, size);
return msg_zerocopy_alloc(sk, size, devmem);
}
EXPORT_SYMBOL_GPL(msg_zerocopy_realloc);
@ -1842,7 +1844,8 @@ 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 ubuf_info *uarg,
struct net_devmem_dmabuf_binding *binding)
{
int err, orig_len = skb->len;
@ -1861,7 +1864,8 @@ 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;

5
net/core/sock.c
View file

@ -3018,6 +3018,11 @@ int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
return -EPERM;
sockc->priority = *(u32 *)CMSG_DATA(cmsg);
break;
case SCM_DEVMEM_DMABUF:
if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
return -EINVAL;
sockc->dmabuf_id = *(u32 *)CMSG_DATA(cmsg);
break;
default:
return -EINVAL;
}

3
net/ipv4/ip_output.c
View file

@ -1014,7 +1014,8 @@ static int __ip_append_data(struct sock *sk,
uarg = msg->msg_ubuf;
}
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb),
false);
if (!uarg)
return -ENOBUFS;
extra_uref = !skb_zcopy(skb); /* only ref on new uarg */

48
net/ipv4/tcp.c
View file

@ -1059,6 +1059,7 @@ 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;
@ -1066,11 +1067,23 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
int flags, err, copied = 0;
int mss_now = 0, size_goal, copied_syn = 0;
int process_backlog = 0;
bool sockc_valid = true;
int zc = 0;
long timeo;
flags = msg->msg_flags;
sockc = (struct sockcm_cookie){ .tsflags = READ_ONCE(sk->sk_tsflags) };
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err))
/* Don't return error until MSG_FASTOPEN has been
* processed; that may succeed even if the cmsg is
* invalid.
*/
sockc_valid = false;
}
if ((flags & MSG_ZEROCOPY) && size) {
if (msg->msg_ubuf) {
uarg = msg->msg_ubuf;
@ -1078,7 +1091,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
zc = MSG_ZEROCOPY;
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
skb = tcp_write_queue_tail(sk);
uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb));
uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb),
sockc_valid && !!sockc.dmabuf_id);
if (!uarg) {
err = -ENOBUFS;
goto out_err;
@ -1087,12 +1101,27 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
zc = MSG_ZEROCOPY;
else
uarg_to_msgzc(uarg)->zerocopy = 0;
if (sockc_valid && sockc.dmabuf_id) {
binding = net_devmem_get_binding(sk, sockc.dmabuf_id);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
binding = NULL;
goto out_err;
}
}
}
} else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
if (sk->sk_route_caps & NETIF_F_SG)
zc = MSG_SPLICE_PAGES;
}
if (sockc_valid && sockc.dmabuf_id &&
(!(flags & MSG_ZEROCOPY) || !sock_flag(sk, SOCK_ZEROCOPY))) {
err = -EINVAL;
goto out_err;
}
if (unlikely(flags & MSG_FASTOPEN ||
inet_test_bit(DEFER_CONNECT, sk)) &&
!tp->repair) {
@ -1131,13 +1160,10 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
/* 'common' sending to sendq */
}
sockc = (struct sockcm_cookie) { .tsflags = READ_ONCE(sk->sk_tsflags)};
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err)) {
if (!sockc_valid) {
if (!err)
err = -EINVAL;
goto out_err;
}
goto out_err;
}
/* This should be in poll */
@ -1258,7 +1284,8 @@ new_segment:
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;
@ -1339,6 +1366,8 @@ out_nopush:
/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
if (uarg && !msg->msg_ubuf)
net_zcopy_put(uarg);
if (binding)
net_devmem_dmabuf_binding_put(binding);
return copied + copied_syn;
do_error:
@ -1356,6 +1385,9 @@ out_err:
sk->sk_write_space(sk);
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
if (binding)
net_devmem_dmabuf_binding_put(binding);
return err;
}
EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);

3
net/ipv6/ip6_output.c
View file

@ -1524,7 +1524,8 @@ emsgsize:
uarg = msg->msg_ubuf;
}
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb),
false);
if (!uarg)
return -ENOBUFS;
extra_uref = !skb_zcopy(skb); /* only ref on new uarg */

5
net/vmw_vsock/virtio_transport_common.c
View file

@ -87,7 +87,7 @@ static int virtio_transport_init_zcopy_skb(struct vsock_sock *vsk,
uarg = msg_zerocopy_realloc(sk_vsock(vsk),
iter->count,
NULL);
NULL, false);
if (!uarg)
return -1;
@ -107,8 +107,7 @@ 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);
&info->msg->msg_iter, len, NULL);
return memcpy_from_msg(skb_put(skb, len), info->msg, len);
}