[PATCH net-next 4/5] io_uring/net: move charging socket out of zc io_uring

Pavel Begunkov
2024-06-27T12:59:48Z

Currently, io_uring's io_sg_from_iter() duplicates the part of
__zerocopy_sg_from_iter() charging pages to the socket. It'd be too easy
to miss while changing it in net/, the chunk is not the most
straightforward for outside users and full of internal implementation
details. io_uring is not a good place to keep it, deduplicate it by
moving out of the callback into __zerocopy_sg_from_iter().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
include/linux/skbuff.h | 3 +++
include/linux/socket.h | 2 +-
io_uring/net.c | 16 ++++------------
net/core/datagram.c | 10 +++++-----
4 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f4cda3fbdb75..9c29bdd5596d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1703,6 +1703,9 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, struct iov_iter *from,
size_t length);

+int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
+ struct iov_iter *from, size_t length);
+
static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb,
struct msghdr *msg, int len)
{
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 89d16b90370b..2a1ff91d1914 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -76,7 +76,7 @@ struct msghdr {
__kernel_size_t msg_controllen; /* ancillary data buffer length */
struct kiocb *msg_iocb; /* ptr to iocb for async requests */
struct ubuf_info *msg_ubuf;
- int (*sg_from_iter)(struct sock *sk, struct sk_buff *skb,
+ int (*sg_from_iter)(struct sk_buff *skb,
struct iov_iter *from, size_t length);
};

diff --git a/io_uring/net.c b/io_uring/net.c
index 7c98c4d50946..84a7602bcef1 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1265,14 +1265,14 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return io_sendmsg_prep_setup(req, req->opcode == IORING_OP_SENDMSG_ZC);
}

-static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
+static int io_sg_from_iter_iovec(struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
skb_zcopy_downgrade_managed(skb);
- return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
+ return zerocopy_fill_skb_from_iter(skb, from, length);
}

-static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
+static int io_sg_from_iter(struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
@@ -1285,7 +1285,7 @@ static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
if (!frag)
shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
else if (unlikely(!skb_zcopy_managed(skb)))
- return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
+ return zerocopy_fill_skb_from_iter(skb, from, length);

bi.bi_size = min(from->count, length);
bi.bi_bvec_done = from->iov_offset;
@@ -1312,14 +1312,6 @@ static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
skb->data_len += copied;
skb->len += copied;
skb->truesize += truesize;
-
- if (sk && sk->sk_type == SOCK_STREAM) {
- sk_wmem_queued_add(sk, truesize);
- if (!skb_zcopy_pure(skb))
- sk_mem_charge(sk, truesize);
- } else {
- refcount_add(truesize, &skb->sk->sk_wmem_alloc);
- }
return ret;
}

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 2b24d69b1e94..554316c40883 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -610,8 +610,8 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
}
EXPORT_SYMBOL(skb_copy_datagram_from_iter);

-static int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
- struct iov_iter *from, size_t length)
+int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
+ struct iov_iter *from, size_t length)
{
int frag = skb_shinfo(skb)->nr_frags;

@@ -687,11 +687,11 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
int ret;

if (msg && msg->msg_ubuf && msg->sg_from_iter)
- return msg->sg_from_iter(sk, skb, from, length);
+ ret = msg->sg_from_iter(skb, from, length);
+ else
+ ret = zerocopy_fill_skb_from_iter(skb, from, length);

- ret = zerocopy_fill_skb_from_iter(skb, from, length);
truesize = skb->truesize - orig_size;
-
if (sk && sk->sk_type == SOCK_STREAM) {
sk_wmem_queued_add(sk, truesize);
if (!skb_zcopy_pure(skb))
--
2.44.0