io_uring: refactor io_read for unsupported nowait

!io_file_supports_async() case of io_read() is hard to read, it jumps
somewhere in the middle of the function just to do async setup and fail
on a similar check. Call io_setup_async_rw() directly for this case,
it's much easier to follow.

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 dcb9e93..866e0ea 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3506,7 +3506,6 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
        struct iov_iter __iter, *iter = &__iter;
        struct io_async_rw *rw = req->async_data;
        ssize_t io_size, ret, ret2;
-       bool no_async;
 
        if (rw) {
                iter = &rw->iter;
@@ -3527,9 +3526,12 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
                kiocb->ki_flags |= IOCB_NOWAIT;
 
        /* If the file doesn't support async, just async punt */
-       no_async = force_nonblock && !io_file_supports_async(req->file, READ);
-       if (no_async)
-               goto copy_iov;
+       if (force_nonblock && !io_file_supports_async(req->file, READ)) {
+               ret = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
+               if (!ret)
+                       return -EAGAIN;
+               goto out_free;
+       }
 
        ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), io_size);
        if (unlikely(ret))
@@ -3568,8 +3570,6 @@ copy_iov:
                ret = ret2;
                goto out_free;
        }
-       if (no_async)
-               return -EAGAIN;
        rw = req->async_data;
        /* it's copied and will be cleaned with ->io */
        iovec = NULL;