io_uring: cleanup io_import_iovec() of pre-mapped request

io_rw_prep_async() goes through a dance of clearing req->io, calling
the iovec import, then re-setting req->io. Provide an internal helper
that does the right thing without needing state tweaked to get there.

This enables further cleanups in io_read, io_write, and
io_resubmit_prep(), but that's left for another time.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4b102d9ad846f9c6cf466b6c093e70ed577dfd28..e325895d681bfd1f67cf3451475ae904efa10758 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2819,22 +2819,15 @@ static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
        return __io_iov_buffer_select(req, iov, needs_lock);
 }
 
-static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
-                              struct iovec **iovec, struct iov_iter *iter,
-                              bool needs_lock)
+static ssize_t __io_import_iovec(int rw, struct io_kiocb *req,
+                                struct iovec **iovec, struct iov_iter *iter,
+                                bool needs_lock)
 {
        void __user *buf = u64_to_user_ptr(req->rw.addr);
        size_t sqe_len = req->rw.len;
        ssize_t ret;
        u8 opcode;
 
-       if (req->io) {
-               struct io_async_rw *iorw = &req->io->rw;
-
-               *iovec = NULL;
-               return iov_iter_count(&iorw->iter);
-       }
-
        opcode = req->opcode;
        if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
                *iovec = NULL;
@@ -2879,6 +2872,16 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
        return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
 }
 
+static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
+                              struct iovec **iovec, struct iov_iter *iter,
+                              bool needs_lock)
+{
+       if (!req->io)
+               return __io_import_iovec(rw, req, iovec, iter, needs_lock);
+       *iovec = NULL;
+       return iov_iter_count(&req->io->rw.iter);
+}
+
 /*
  * For files that don't have ->read_iter() and ->write_iter(), handle them
  * by looping over ->read() or ->write() manually.
@@ -3001,11 +3004,8 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
        ssize_t ret;
 
        iorw->iter.iov = iorw->fast_iov;
-       /* reset ->io around the iovec import, we don't want to use it */
-       req->io = NULL;
-       ret = io_import_iovec(rw, req, (struct iovec **) &iorw->iter.iov,
+       ret = __io_import_iovec(rw, req, (struct iovec **) &iorw->iter.iov,
                                &iorw->iter, !force_nonblock);
-       req->io = container_of(iorw, struct io_async_ctx, rw);
        if (unlikely(ret < 0))
                return ret;