Commit 257e84a5 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: refactor sendmsg/recvmsg iov managing 



Current iov handling with recvmsg/sendmsg may be confusing. First make a
rule for msg->iov: either it points to an allocated iov that have to be
kfree()'d later, or it's NULL and we use fast_iov. That's much better
than current 3-state (also can point to fast_iov). And rename it into
free_iov for uniformity with read/write.

Also, instead of after struct io_async_msghdr copy fixing up of
msg.msg_iter.iov has been happening in io_recvmsg()/io_sendmsg(). Move
it into io_setup_async_msg(), that's the right place.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
[axboe: add comment on NULL check before kfree()]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5476dfed

fs/io_uring.c

+27 −30
Original line number Diff line number Diff line
@@ -594,7 +594,8 @@ struct io_async_connect { 


struct io_async_msghdr {

	struct iovec			fast_iov[UIO_FASTIOV];

	struct iovec			*iov;

	/* points to an allocated iov, if NULL we use fast_iov instead */

	struct iovec			*free_iov;

	struct sockaddr __user		*uaddr;

	struct msghdr			msg;

	struct sockaddr_storage		addr;
@@ -4551,24 +4552,27 @@ static int io_setup_async_msg(struct io_kiocb *req, 
	if (async_msg)

		return -EAGAIN;

	if (io_alloc_async_data(req)) {

		if (kmsg->iov != kmsg->fast_iov)

			kfree(kmsg->iov);

		kfree(kmsg->free_iov);

		return -ENOMEM;

	}

	async_msg = req->async_data;

	req->flags |= REQ_F_NEED_CLEANUP;

	memcpy(async_msg, kmsg, sizeof(*kmsg));

	async_msg->msg.msg_name = &async_msg->addr;

	/* if were using fast_iov, set it to the new one */

	if (!async_msg->free_iov)

		async_msg->msg.msg_iter.iov = async_msg->fast_iov;



	return -EAGAIN;

}



static int io_sendmsg_copy_hdr(struct io_kiocb *req,

			       struct io_async_msghdr *iomsg)

{

	iomsg->iov = iomsg->fast_iov;

	iomsg->msg.msg_name = &iomsg->addr;

	iomsg->free_iov = iomsg->fast_iov;

	return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,

				   req->sr_msg.msg_flags, &iomsg->iov);

				   req->sr_msg.msg_flags, &iomsg->free_iov);

}



static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
@@ -4609,13 +4613,8 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock, 
	if (unlikely(!sock))

		return -ENOTSOCK;



	if (req->async_data) {

	kmsg = req->async_data;

		/* if iov is set, it's allocated already */

		if (!kmsg->iov)

			kmsg->iov = kmsg->fast_iov;

		kmsg->msg.msg_iter.iov = kmsg->iov;

	} else {

	if (!kmsg) {

		ret = io_sendmsg_copy_hdr(req, &iomsg);

		if (ret)

			return ret;
@@ -4634,8 +4633,9 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock, 
	if (ret == -ERESTARTSYS)

		ret = -EINTR;



	if (kmsg->iov != kmsg->fast_iov)

		kfree(kmsg->iov);

	/* fast path, check for non-NULL to avoid function call */

	if (kmsg->free_iov)

		kfree(kmsg->free_iov);

	req->flags &= ~REQ_F_NEED_CLEANUP;

	if (ret < 0)

		req_set_fail_links(req);
@@ -4704,10 +4704,11 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *req, 
		if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov)))

			return -EFAULT;

		sr->len = iomsg->fast_iov[0].iov_len;

		iomsg->iov = NULL;

		iomsg->free_iov = NULL;

	} else {

		iomsg->free_iov = iomsg->fast_iov;

		ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,

				     &iomsg->iov, &iomsg->msg.msg_iter,

				     &iomsg->free_iov, &iomsg->msg.msg_iter,

				     false);

		if (ret > 0)

			ret = 0;
@@ -4746,10 +4747,11 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, 
		if (clen < 0)

			return -EINVAL;

		sr->len = clen;

		iomsg->iov = NULL;

		iomsg->free_iov = NULL;

	} else {

		iomsg->free_iov = iomsg->fast_iov;

		ret = __import_iovec(READ, (struct iovec __user *)uiov, len,

				   UIO_FASTIOV, &iomsg->iov,

				   UIO_FASTIOV, &iomsg->free_iov,

				   &iomsg->msg.msg_iter, true);

		if (ret < 0)

			return ret;
@@ -4763,7 +4765,6 @@ static int io_recvmsg_copy_hdr(struct io_kiocb *req, 
			       struct io_async_msghdr *iomsg)

{

	iomsg->msg.msg_name = &iomsg->addr;

	iomsg->iov = iomsg->fast_iov;



#ifdef CONFIG_COMPAT

	if (req->ctx->compat)
@@ -4834,13 +4835,8 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock, 
	if (unlikely(!sock))

		return -ENOTSOCK;



	if (req->async_data) {

	kmsg = req->async_data;

		/* if iov is set, it's allocated already */

		if (!kmsg->iov)

			kmsg->iov = kmsg->fast_iov;

		kmsg->msg.msg_iter.iov = kmsg->iov;

	} else {

	if (!kmsg) {

		ret = io_recvmsg_copy_hdr(req, &iomsg);

		if (ret)

			return ret;
@@ -4872,8 +4868,9 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock, 


	if (req->flags & REQ_F_BUFFER_SELECTED)

		cflags = io_put_recv_kbuf(req);

	if (kmsg->iov != kmsg->fast_iov)

		kfree(kmsg->iov);

	/* fast path, check for non-NULL to avoid function call */

	if (kmsg->free_iov)

		kfree(kmsg->free_iov);

	req->flags &= ~REQ_F_NEED_CLEANUP;

	if (ret < 0)

		req_set_fail_links(req);
@@ -6166,8 +6163,8 @@ static void __io_clean_op(struct io_kiocb *req) 
		case IORING_OP_RECVMSG:

		case IORING_OP_SENDMSG: {

			struct io_async_msghdr *io = req->async_data;

			if (io->iov != io->fast_iov)

				kfree(io->iov);



			kfree(io->free_iov);

			break;

			}

		case IORING_OP_SPLICE: