[PATCH v2 6/9] io_uring: kill REQ_F_LTIMEOUT_ACTIVE

Pavel Begunkov
2021-08-15T09:41:11Z

Instead of handling double consecutive linked timeouts through tricky
flag combinations, just check the submit_state.link during timeout_prep
and fail that case in advance.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a0d081dca389..ece69b1217c8 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -705,7 +705,6 @@ enum {
REQ_F_NEED_CLEANUP_BIT,
REQ_F_POLLED_BIT,
REQ_F_BUFFER_SELECTED_BIT,
- REQ_F_LTIMEOUT_ACTIVE_BIT,
REQ_F_COMPLETE_INLINE_BIT,
REQ_F_REISSUE_BIT,
REQ_F_DONT_REISSUE_BIT,
@@ -750,8 +749,6 @@ enum {
REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
/* buffer already selected */
REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT),
- /* linked timeout is active, i.e. prepared by link's head */
- REQ_F_LTIMEOUT_ACTIVE = BIT(REQ_F_LTIMEOUT_ACTIVE_BIT),
/* completion is deferred through io_comp_state */
REQ_F_COMPLETE_INLINE = BIT(REQ_F_COMPLETE_INLINE_BIT),
/* caller should reissue async */
@@ -1313,7 +1310,6 @@ static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
__io_req_set_refcount(nxt, 2);

nxt->timeout.head = req;
- nxt->flags |= REQ_F_LTIMEOUT_ACTIVE;
req->flags |= REQ_F_LINK_TIMEOUT;
return nxt;
}
@@ -1893,11 +1889,7 @@ static bool io_kill_linked_timeout(struct io_kiocb *req)
{
struct io_kiocb *link = req->link;

- /*
- * Can happen if a linked timeout fired and link had been like
- * req -> link t-out -> link t-out [-> ...]
- */
- if (link && (link->flags & REQ_F_LTIMEOUT_ACTIVE)) {
+ if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
struct io_timeout_data *io = link->async_data;

io_remove_next_linked(req);
@@ -5698,6 +5690,15 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,

data->mode = io_translate_timeout_mode(flags);
hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
+
+ if (is_timeout_link) {
+ struct io_submit_link *link = &req->ctx->submit_state.link;
+
+ if (!link->head)
+ return -EINVAL;
+ if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
+ return -EINVAL;
+ }
return 0;
}

--
2.32.0