unimore/kernel-hacking-2024-linux-steffo
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io_uring/net: add non-bvec sg chunking callback

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Add a sg_from_iter() for when we initiate non-bvec zerocopy sends, which
helps us to remove some extra steps from io_sg_from_iter(). The only
thing the new function has to do before giving control away to
__zerocopy_sg_from_iter() is to check if the skb has managed frags and
downgrade them if so.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cda3dea0d36f7931f63a70f350130f085ac3f3dd.1662639236.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2022-09-08 13:20:32 +01:00 committed by Jens Axboe
parent 6bf8ad25fc
commit cd9021e88f
1 changed files with 11 additions and 6 deletions
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17
io_uring/net.c
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@ -948,6 +948,13 @@ int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return 0;
}
static int io_sg_from_iter_iovec(struct sock *sk, 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);
}
static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
@ -958,13 +965,10 @@ static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
ssize_t copied = 0;
unsigned long truesize = 0;
if (!shinfo->nr_frags)
if (!frag)
shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
if (!skb_zcopy_managed(skb) || !iov_iter_is_bvec(from)) {
skb_zcopy_downgrade_managed(skb);
else if (unlikely(!skb_zcopy_managed(skb)))
return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
}
bi.bi_size = min(from->count, length);
bi.bi_bvec_done = from->iov_offset;
@ -1045,6 +1049,7 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
(u64)(uintptr_t)zc->buf, zc->len);
if (unlikely(ret))
return ret;
msg.sg_from_iter = io_sg_from_iter;
} else {
ret = import_single_range(WRITE, zc->buf, zc->len, &iov,
&msg.msg_iter);
@ -1053,6 +1058,7 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
ret = io_notif_account_mem(zc->notif, zc->len);
if (unlikely(ret))
return ret;
msg.sg_from_iter = io_sg_from_iter_iovec;
}
msg_flags = zc->msg_flags | MSG_ZEROCOPY;
@ -1063,7 +1069,6 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
msg.msg_flags = msg_flags;
msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
msg.sg_from_iter = io_sg_from_iter;
ret = sock_sendmsg(sock, &msg);
if (unlikely(ret < min_ret)) {