io_uring: use iter_ubuf for single range imports

This is more efficient than iter_iov.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
[merge to 6.2, minor fixes]
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 8227af2..436a2e0 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -391,7 +391,7 @@ static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
                        rw->len = sqe_len;
                }
 
-               ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
+               ret = import_ubuf(ddir, buf, sqe_len, iter);
                if (ret)
                        return ERR_PTR(ret);
                return NULL;
@@ -450,7 +450,10 @@ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
                struct iovec iovec;
                ssize_t nr;
 
-               if (!iov_iter_is_bvec(iter)) {
+               if (iter_is_ubuf(iter)) {
+                       iovec.iov_base = iter->ubuf + iter->iov_offset;
+                       iovec.iov_len = iov_iter_count(iter);
+               } else if (!iov_iter_is_bvec(iter)) {
                        iovec = iov_iter_iovec(iter);
                } else {
                        iovec.iov_base = u64_to_user_ptr(rw->addr);
@@ -495,7 +498,7 @@ static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
        io->free_iovec = iovec;
        io->bytes_done = 0;
        /* can only be fixed buffers, no need to do anything */
-       if (iov_iter_is_bvec(iter))
+       if (iov_iter_is_bvec(iter) || iter_is_ubuf(iter))
                return;
        if (!iovec) {
                unsigned iov_off = 0;