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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>
This commit is contained in:
Jens Axboe 2019-12-11 19:29:43 -07:00
parent 6e802a4ba0
commit 0c9d5ccd26
3 changed files with 12 additions and 2 deletions
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8
fs/io-wq.c
View File

@ -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;
}

1
fs/io-wq.h
View File

@ -12,6 +12,7 @@ enum {
IO_WQ_WORK_UNBOUND = 32,
IO_WQ_WORK_INTERNAL = 64,
IO_WQ_WORK_CB = 128,
IO_WQ_WORK_NO_CANCEL = 256,
IO_WQ_HASH_SHIFT = 24, /* upper 8 bits are used for hash key */
};

5
fs/io_uring.c
View File

@ -3460,8 +3460,11 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
struct io_kiocb *nxt = NULL;
int ret = 0;
if (work->flags & IO_WQ_WORK_CANCEL)
/* if NO_CANCEL is set, we must still run the work */
if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) ==
IO_WQ_WORK_CANCEL) {
ret = -ECANCELED;
}
if (!ret) {
req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0;