| Message ID | 20220721131325.624788-1-dylany@fb.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: do not recycle buffer in READV | expand |
On Thu, 21 Jul 2022 06:13:25 -0700, Dylan Yudaken wrote: > READV cannot recycle buffers as it would lose some of the data required to > reimport that buffer. > > Applied, thanks! [1/1] io_uring: do not recycle buffer in READV commit: 934447a603b22d98f45a679115d8402e1efdd0f7 Best regards,
diff --git a/fs/io_uring.c b/fs/io_uring.c index a01ea49f3017..b0180679584f 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.
READV cannot recycle buffers as it would lose some of the data required to reimport that buffer. Reported-by: Ammar Faizi <ammarfaizi2@gnuweeb.org> Fixes: b66e65f41426 ("io_uring: never call io_buffer_select() for a buffer re-select") Signed-off-by: Dylan Yudaken <dylany@fb.com> --- I think going forward we can probably re-enable recycling for READV, or perhaps stick it in the opdef to make it a bit more general. However since it is late in the merge cycle I thought the simplest approach is best. Worth noting the initial discussed approach of stashing the data in `struct io_rw` would not have worked as that struct is full already apparently. Dylan fs/io_uring.c | 8 ++++++++ 1 file changed, 8 insertions(+) base-commit: ff6992735ade75aae3e35d16b17da1008d753d28