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io_uring/io-wq: forward submission ref to async

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First it changes io-wq interfaces. It replaces {get,put}_work() with
free_work(), which guaranteed to be called exactly once. It also enforces
free_work() callback to be non-NULL.

io_uring follows the changes and instead of putting a submission reference
in io_put_req_async_completion(), it will be done in io_free_work(). As
removes io_get_work() with corresponding refcount_inc(), the ref balance
is maintained.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov
2020-03-04 16:14:12 +03:00
committed by Jens Axboe
parent f462fd36fc
commit e9fd939654
3 changed files with 27 additions and 39 deletions
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29
fs/io-wq.c
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@@ -107,8 +107,7 @@ struct io_wq {
struct io_wqe **wqes;
unsigned long state;
get_work_fn *get_work;
put_work_fn *put_work;
free_work_fn *free_work;
struct task_struct *manager;
struct user_struct *user;
@@ -509,16 +508,11 @@ get_next:
if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
work->flags |= IO_WQ_WORK_CANCEL;
if (wq->get_work)
wq->get_work(work);
old_work = work;
work->func(&work);
work = (old_work == work) ? NULL : work;
io_assign_current_work(worker, work);
if (wq->put_work)
wq->put_work(old_work);
wq->free_work(old_work);
if (hash != -1U) {
spin_lock_irq(&wqe->lock);
@@ -749,14 +743,17 @@ static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
return true;
}
static void io_run_cancel(struct io_wq_work *work)
static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
{
struct io_wq *wq = wqe->wq;
do {
struct io_wq_work *old_work = work;
work->flags |= IO_WQ_WORK_CANCEL;
work->func(&work);
work = (work == old_work) ? NULL : work;
wq->free_work(old_work);
} while (work);
}
@@ -773,7 +770,7 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
* It's close enough to not be an issue, fork() has the same delay.
*/
if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
io_run_cancel(work);
io_run_cancel(work, wqe);
return;
}
@@ -912,7 +909,7 @@ static enum io_wq_cancel io_wqe_cancel_cb_work(struct io_wqe *wqe,
spin_unlock_irqrestore(&wqe->lock, flags);
if (found) {
io_run_cancel(work);
io_run_cancel(work, wqe);
return IO_WQ_CANCEL_OK;
}
@@ -987,7 +984,7 @@ static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
spin_unlock_irqrestore(&wqe->lock, flags);
if (found) {
io_run_cancel(work);
io_run_cancel(work, wqe);
return IO_WQ_CANCEL_OK;
}
@@ -1064,6 +1061,9 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
int ret = -ENOMEM, node;
struct io_wq *wq;
if (WARN_ON_ONCE(!data->free_work))
return ERR_PTR(-EINVAL);
wq = kzalloc(sizeof(*wq), GFP_KERNEL);
if (!wq)
return ERR_PTR(-ENOMEM);
@@ -1074,8 +1074,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
return ERR_PTR(-ENOMEM);
}
wq->get_work = data->get_work;
wq->put_work = data->put_work;
wq->free_work = data->free_work;
/* caller must already hold a reference to this */
wq->user = data->user;
@@ -1132,7 +1131,7 @@ err:
bool io_wq_get(struct io_wq *wq, struct io_wq_data *data)
{
if (data->get_work != wq->get_work || data->put_work != wq->put_work)
if (data->free_work != wq->free_work)
return false;
return refcount_inc_not_zero(&wq->use_refs);