Re: [PATCH 1/1] io_uring/net: send retry for zerocopy

[Stefan Metzmacher <metze@samba.org>]

Hi Pavel,

> io_uring handles short sends/recvs for stream sockets when MSG_WAITALL
> is set, however new zerocopy send is inconsistent in this regard, which
> might be confusing. Handle short sends.
> 
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>   io_uring/net.c | 20 +++++++++++++++++---
>   1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/io_uring/net.c b/io_uring/net.c
> index 32fc3da04e41..f9f080b3cc1e 100644
> --- a/io_uring/net.c
> +++ b/io_uring/net.c
> @@ -70,6 +70,7 @@ struct io_sendzc {
>   	unsigned			flags;
>   	unsigned			addr_len;
>   	void __user			*addr;
> +	size_t				done_io;
>   };
>   
>   #define IO_APOLL_MULTI_POLLED (REQ_F_APOLL_MULTISHOT | REQ_F_POLLED)
> @@ -878,6 +879,7 @@ int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>   
>   	zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
>   	zc->addr_len = READ_ONCE(sqe->addr_len);
> +	zc->done_io = 0;
>   
>   #ifdef CONFIG_COMPAT
>   	if (req->ctx->compat)
> @@ -1012,11 +1014,23 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
>   	if (unlikely(ret < min_ret)) {
>   		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
>   			return -EAGAIN;
> -		return ret == -ERESTARTSYS ? -EINTR : ret;
> +		if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
> +			zc->len -= ret;
> +			zc->buf += ret;
> +			zc->done_io += ret;
> +			req->flags |= REQ_F_PARTIAL_IO;

Don't we need a prep_async function and/or something like
io_setup_async_msg() here to handle address?

metze