From 257e84a5377fbbc336ff563833a8712619acce56 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 5 Feb 2021 00:58:00 +0000 Subject: 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: Pavel Begunkov [axboe: add comment on NULL check before kfree()] Signed-off-by: Jens Axboe --- fs/io_uring.c | 57 +++++++++++++++++++++++++++------------------------------ 1 file changed, 27 insertions(+), 30 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index e07a7fa15cfa..7242cc48e97b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -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 { + kmsg = req->async_data; + 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 { + kmsg = req->async_data; + 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: -- cgit v1.2.3