io_uring: fix provided buffer import

io_import_iovec uses the s pointer, but this was changed immediately
after the iovec was re-imported and so it was imported into the wrong
place.

Change the ordering.

Fixes: f2fc9832203d ("io_uring: ensure reads re-import for selected buffers")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630132006.2825668-1-dylany@fb.com
[axboe: ensure we don't half-import as well]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index aeb042ba5cc533023b66818d84db0995a9a24a0e..0d491ad15b66ad92eb12b480331b32e841675281 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4318,18 +4318,19 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
                if (unlikely(ret < 0))
                        return ret;
        } else {
+               rw = req->async_data;
+               s = &rw->s;
+
                /*
                 * Safe and required to re-import if we're using provided
                 * buffers, as we dropped the selected one before retry.
                 */
-               if (req->flags & REQ_F_BUFFER_SELECT) {
+               if (io_do_buffer_select(req)) {
                        ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
                        if (unlikely(ret < 0))
                                return ret;
                }
 
-               rw = req->async_data;
-               s = &rw->s;
                /*
                 * We come here from an earlier attempt, restore our state to
                 * match in case it doesn't. It's cheap enough that we don't