io-wq: add support for uncancellable work
Not all work can be cancelled, some of it we may need to guarantee
that it runs to completion. Allow the caller to set IO_WQ_WORK_NO_CANCEL
on work that must not be cancelled. Note that the caller work function
must also check for IO_WQ_WORK_NO_CANCEL on work that is marked
IO_WQ_WORK_CANCEL.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 5147d22..79eae29 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -456,6 +456,10 @@ static void io_worker_handle_work(struct io_worker *worker)
}
if (!worker->creds)
worker->creds = override_creds(wq->creds);
+ /*
+ * OK to set IO_WQ_WORK_CANCEL even for uncancellable work,
+ * the worker function will do the right thing.
+ */
if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
work->flags |= IO_WQ_WORK_CANCEL;
if (worker->mm)
@@ -828,6 +832,7 @@ static bool io_work_cancel(struct io_worker *worker, void *cancel_data)
*/
spin_lock_irqsave(&worker->lock, flags);
if (worker->cur_work &&
+ !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) &&
data->cancel(worker->cur_work, data->caller_data)) {
send_sig(SIGINT, worker->task, 1);
ret = true;
@@ -902,7 +907,8 @@ static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
return false;
spin_lock_irqsave(&worker->lock, flags);
- if (worker->cur_work == work) {
+ if (worker->cur_work == work &&
+ !(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL)) {
send_sig(SIGINT, worker->task, 1);
ret = true;
}
