On 4/12/23 23:27, David Wei wrote:
A multishot timeout submission will repeatedly generate completions with
the IORING_CQE_F_MORE cflag set. Depending on the value of the `off' field
in the submission, these timeouts can either repeat indefinitely until
cancelled (`off' = 0) or for a fixed number of times (`off' > 0).
Only noseq timeouts (i.e. not dependent on the number of I/O
completions) are supported.
An indefinite timer will be cancelled with EOVERFLOW if the CQ ever
overflows.
Seems mostly fine, two comments below
Signed-off-by: David Wei <davidhwei@xxxxxxxx>
---
include/uapi/linux/io_uring.h | 1 +
io_uring/timeout.c | 59 +++++++++++++++++++++++++++++++++--
2 files changed, 57 insertions(+), 3 deletions(-)
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index f8d14d1c58d3..0716cb17e436 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -250,6 +250,7 @@ enum io_uring_op {
#define IORING_TIMEOUT_REALTIME (1U << 3)
#define IORING_LINK_TIMEOUT_UPDATE (1U << 4)
#define IORING_TIMEOUT_ETIME_SUCCESS (1U << 5)
+#define IORING_TIMEOUT_MULTISHOT (1U << 6)
#define IORING_TIMEOUT_CLOCK_MASK (IORING_TIMEOUT_BOOTTIME | IORING_TIMEOUT_REALTIME)
#define IORING_TIMEOUT_UPDATE_MASK (IORING_TIMEOUT_UPDATE | IORING_LINK_TIMEOUT_UPDATE)
/*
diff --git a/io_uring/timeout.c b/io_uring/timeout.c
index 5c6c6f720809..61b8488565ce 100644
...
+static void io_timeout_complete(struct io_kiocb *req, struct io_tw_state *ts)
+{
+ struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+ struct io_timeout_data *data = req->async_data;
+ struct io_ring_ctx *ctx = req->ctx;
+
+ if (!io_timeout_finish(timeout, data)) {
+ bool filled;
+ filled = io_aux_cqe(ctx, false, req->cqe.user_data, -ETIME,
+ IORING_CQE_F_MORE, false);
+ if (filled) {
+ /* re-arm timer */
+ spin_lock_irq(&ctx->timeout_lock);
+ list_add(&timeout->list, ctx->timeout_list.prev);
+ data->timer.function = io_timeout_fn;
+ hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
+ spin_unlock_irq(&ctx->timeout_lock);
+ return;
+ }
+ io_req_set_res(req, -EOVERFLOW, 0);
Let's not change the return value. It's considered a normal completion
and we don't change the code for them. And there is IORING_CQE_F_MORE
for userspace to figure out that it has been terminated.
+ }
+
+ io_req_task_complete(req, ts);
+}
+
static bool io_kill_timeout(struct io_kiocb *req, int status)
__must_hold(&req->ctx->timeout_lock)
{
@@ -212,7 +253,7 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
req_set_fail(req);
io_req_set_res(req, -ETIME, 0);
- req->io_task_work.func = io_req_task_complete;
+ req->io_task_work.func = io_timeout_complete;
io_req_task_work_add(req);
return HRTIMER_NORESTART;
}
@@ -470,16 +511,28 @@ static int __io_timeout_prep(struct io_kiocb *req,
return -EINVAL;
flags = READ_ONCE(sqe->timeout_flags);
if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
- IORING_TIMEOUT_ETIME_SUCCESS))
+ IORING_TIMEOUT_ETIME_SUCCESS |
+ IORING_TIMEOUT_MULTISHOT)) {
return -EINVAL;
+ }
Please, don't add braces, they're not needed here.
/* more than one clock specified is invalid, obviously */
if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
return -EINVAL;
+ /* multishot requests only make sense with rel values */
+ if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
+ return -EINVAL;
INIT_LIST_HEAD(&timeout->list);
timeout->off = off;
if (unlikely(off && !req->ctx->off_timeout_used))
req->ctx->off_timeout_used = true;
+ /*
+ * for multishot reqs w/ fixed nr of repeats, target_seq tracks the
+ * remaining nr
+ */
+ timeout->repeats = 0;
+ if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
+ timeout->repeats = off;
if (WARN_ON_ONCE(req_has_async_data(req)))
return -EFAULT;
--
Pavel Begunkov
