io_uring/net: set MSG_ZEROCOPY for sendzc in advance

We can set MSG_ZEROCOPY at the preparation step, do it so we don't have
to care about it later in the issue callback.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c2c22aaa577624977f045979a6db2b9fb2e5648c.1712534031.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/net.c

@@ -1050,7 +1050,7 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	zc->len = READ_ONCE(sqe->len);
-	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
+	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL | MSG_ZEROCOPY;
 	if (zc->msg_flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 
@@ -1167,7 +1167,7 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
 			return ret;
 	}
 
-	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
+	msg_flags = zc->msg_flags;
 	if (issue_flags & IO_URING_F_NONBLOCK)
 		msg_flags |= MSG_DONTWAIT;
 	if (msg_flags & MSG_WAITALL)
@@ -1229,7 +1229,7 @@ int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
 		return -EAGAIN;
 
-	flags = sr->msg_flags | MSG_ZEROCOPY;
+	flags = sr->msg_flags;
 	if (issue_flags & IO_URING_F_NONBLOCK)
 		flags |= MSG_DONTWAIT;
 	if (flags & MSG_WAITALL)