io_uring: use more specific type in rcv/snd msg cp

send/recv msghdr initialisation works with struct io_async_msghdr, but
pulls the whole struct io_async_ctx for no reason. That complicates it
with composite accessing, e.g. io->msg.

Use and pass the most specific type, which is struct io_async_msghdr.
It is the larget field in union io_async_ctx and doesn't save stack
space, but looks clearer.
The most of the changes are replacing "io->msg." with "iomsg->"

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f17f098c403a3e50f63d852d5604fe9ca64efe8c..8acbaddaebb7265e49c542223058dc44f30fca9c 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3935,7 +3935,7 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 
        sock = sock_from_file(req->file, &ret);
        if (sock) {
-               struct io_async_ctx io;
+               struct io_async_msghdr iomsg;
                unsigned flags;
 
                if (req->io) {
@@ -3948,14 +3948,13 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
                } else {
                        struct io_sr_msg *sr = &req->sr_msg;
 
-                       kmsg = &io.msg;
-                       kmsg->msg.msg_name = &io.msg.addr;
-
-                       io.msg.iov = io.msg.fast_iov;
-                       ret = sendmsg_copy_msghdr(&io.msg.msg, sr->umsg,
-                                       sr->msg_flags, &io.msg.iov);
+                       iomsg.msg.msg_name = &iomsg.addr;
+                       iomsg.iov = iomsg.fast_iov;
+                       ret = sendmsg_copy_msghdr(&iomsg.msg, sr->umsg,
+                                       sr->msg_flags, &iomsg.iov);
                        if (ret)
                                return ret;
+                       kmsg = &iomsg;
                }
 
                flags = req->sr_msg.msg_flags;
@@ -4023,30 +4022,31 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
        return 0;
 }
 
-static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
+static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
+                                struct io_async_msghdr *iomsg)
 {
        struct io_sr_msg *sr = &req->sr_msg;
        struct iovec __user *uiov;
        size_t iov_len;
        int ret;
 
-       ret = __copy_msghdr_from_user(&io->msg.msg, sr->umsg,
-                                       &io->msg.uaddr, &uiov, &iov_len);
+       ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
+                                       &iomsg->uaddr, &uiov, &iov_len);
        if (ret)
                return ret;
 
        if (req->flags & REQ_F_BUFFER_SELECT) {
                if (iov_len > 1)
                        return -EINVAL;
-               if (copy_from_user(io->msg.iov, uiov, sizeof(*uiov)))
+               if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov)))
                        return -EFAULT;
-               sr->len = io->msg.iov[0].iov_len;
-               iov_iter_init(&io->msg.msg.msg_iter, READ, io->msg.iov, 1,
+               sr->len = iomsg->iov[0].iov_len;
+               iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1,
                                sr->len);
-               io->msg.iov = NULL;
+               iomsg->iov = NULL;
        } else {
                ret = import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
-                                       &io->msg.iov, &io->msg.msg.msg_iter);
+                                       &iomsg->iov, &iomsg->msg.msg_iter);
                if (ret > 0)
                        ret = 0;
        }
@@ -4056,7 +4056,7 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
 
 #ifdef CONFIG_COMPAT
 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
-                                       struct io_async_ctx *io)
+                                       struct io_async_msghdr *iomsg)
 {
        struct compat_msghdr __user *msg_compat;
        struct io_sr_msg *sr = &req->sr_msg;
@@ -4066,7 +4066,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
        int ret;
 
        msg_compat = (struct compat_msghdr __user *) sr->umsg;
-       ret = __get_compat_msghdr(&io->msg.msg, msg_compat, &io->msg.uaddr,
+       ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr,
                                        &ptr, &len);
        if (ret)
                return ret;
@@ -4083,12 +4083,12 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
                        return -EFAULT;
                if (clen < 0)
                        return -EINVAL;
-               sr->len = io->msg.iov[0].iov_len;
-               io->msg.iov = NULL;
+               sr->len = iomsg->iov[0].iov_len;
+               iomsg->iov = NULL;
        } else {
                ret = compat_import_iovec(READ, uiov, len, UIO_FASTIOV,
-                                               &io->msg.iov,
-                                               &io->msg.msg.msg_iter);
+                                               &iomsg->iov,
+                                               &iomsg->msg.msg_iter);
                if (ret < 0)
                        return ret;
        }
@@ -4097,17 +4097,18 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
 }
 #endif
 
-static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
+static int io_recvmsg_copy_hdr(struct io_kiocb *req,
+                              struct io_async_msghdr *iomsg)
 {
-       io->msg.msg.msg_name = &io->msg.addr;
-       io->msg.iov = io->msg.fast_iov;
+       iomsg->msg.msg_name = &iomsg->addr;
+       iomsg->iov = iomsg->fast_iov;
 
 #ifdef CONFIG_COMPAT
        if (req->ctx->compat)
-               return __io_compat_recvmsg_copy_hdr(req, io);
+               return __io_compat_recvmsg_copy_hdr(req, iomsg);
 #endif
 
-       return __io_recvmsg_copy_hdr(req, io);
+       return __io_recvmsg_copy_hdr(req, iomsg);
 }
 
 static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
@@ -4157,7 +4158,7 @@ static int io_recvmsg_prep(struct io_kiocb *req,
        if (req->flags & REQ_F_NEED_CLEANUP)
                return 0;
 
-       ret = io_recvmsg_copy_hdr(req, io);
+       ret = io_recvmsg_copy_hdr(req, &io->msg);
        if (!ret)
                req->flags |= REQ_F_NEED_CLEANUP;
        return ret;
@@ -4173,7 +4174,7 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
        sock = sock_from_file(req->file, &ret);
        if (sock) {
                struct io_buffer *kbuf;
-               struct io_async_ctx io;
+               struct io_async_msghdr iomsg;
                unsigned flags;
 
                if (req->io) {
@@ -4184,12 +4185,10 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
                                kmsg->iov = kmsg->fast_iov;
                        kmsg->msg.msg_iter.iov = kmsg->iov;
                } else {
-                       kmsg = &io.msg;
-                       kmsg->msg.msg_name = &io.msg.addr;
-
-                       ret = io_recvmsg_copy_hdr(req, &io);
+                       ret = io_recvmsg_copy_hdr(req, &iomsg);
                        if (ret)
                                return ret;
+                       kmsg = &iomsg;
                }
 
                kbuf = io_recv_buffer_select(req, &cflags, !force_nonblock);