From 934447a603b22d98f45a679115d8402e1efdd0f7 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 21 Jul 2022 06:13:25 -0700 Subject: [PATCH] io_uring: do not recycle buffer in READV READV cannot recycle buffers as it would lose some of the data required to reimport that buffer. Reported-by: Ammar Faizi Fixes: b66e65f41426 ("io_uring: never call io_buffer_select() for a buffer re-select") Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220721131325.624788-1-dylany@fb.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 2b7bb62c7805..e8e769be9ed0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1737,6 +1737,14 @@ static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) (req->flags & REQ_F_PARTIAL_IO)) return; + /* + * READV uses fields in `struct io_rw` (len/addr) to stash the selected + * buffer data. However if that buffer is recycled the original request + * data stored in addr is lost. Therefore forbid recycling for now. + */ + if (req->opcode == IORING_OP_READV) + return; + /* * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear * the flag and hence ensure that bl->head doesn't get incremented.