[PATCH 5.7 028/124] io-wq: reorder cancellation pending -> running

Greg Kroah-Hartman
2020-08-24T08:39:58Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit f4c2665e33f48904f2766d644df33fb3fd54b5ec ]

Go all over all pending lists and cancel works there, and only then
try to match running requests. No functional changes here, just a
preparation for bulk cancellation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io-wq.c | 54 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 4023c98468608..3283f8c5b5a18 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -931,19 +931,14 @@ static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
return ret;
}

-static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
- struct io_cb_cancel_data *match)
+static bool io_wqe_cancel_pending_work(struct io_wqe *wqe,
+ struct io_cb_cancel_data *match)
{
struct io_wq_work_node *node, *prev;
struct io_wq_work *work;
unsigned long flags;
bool found = false;

- /*
- * First check pending list, if we're lucky we can just remove it
- * from there. CANCEL_OK means that the work is returned as-new,
- * no completion will be posted for it.
- */
spin_lock_irqsave(&wqe->lock, flags);
wq_list_for_each(node, prev, &wqe->work_list) {
work = container_of(node, struct io_wq_work, list);
@@ -956,21 +951,20 @@ static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
}
spin_unlock_irqrestore(&wqe->lock, flags);

- if (found) {
+ if (found)
io_run_cancel(work, wqe);
- return IO_WQ_CANCEL_OK;
- }
+ return found;
+}
+
+static bool io_wqe_cancel_running_work(struct io_wqe *wqe,
+ struct io_cb_cancel_data *match)
+{
+ bool found;

- /*
- * Now check if a free (going busy) or busy worker has the work
- * currently running. If we find it there, we'll return CANCEL_RUNNING
- * as an indication that we attempt to signal cancellation. The
- * completion will run normally in this case.
- */
rcu_read_lock();
found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
rcu_read_unlock();
- return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
+ return found;
}

enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
@@ -980,18 +974,34 @@ enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
.fn = cancel,
.data = data,
};
- enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
int node;

+ /*
+ * First check pending list, if we're lucky we can just remove it
+ * from there. CANCEL_OK means that the work is returned as-new,
+ * no completion will be posted for it.
+ */
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];

- ret = io_wqe_cancel_work(wqe, &match);
- if (ret != IO_WQ_CANCEL_NOTFOUND)
- break;
+ if (io_wqe_cancel_pending_work(wqe, &match))
+ return IO_WQ_CANCEL_OK;
}

- return ret;
+ /*
+ * Now check if a free (going busy) or busy worker has the work
+ * currently running. If we find it there, we'll return CANCEL_RUNNING
+ * as an indication that we attempt to signal cancellation. The
+ * completion will run normally in this case.
+ */
+ for_each_node(node) {
+ struct io_wqe *wqe = wq->wqes[node];
+
+ if (io_wqe_cancel_running_work(wqe, &match))
+ return IO_WQ_CANCEL_RUNNING;
+ }
+
+ return IO_WQ_CANCEL_NOTFOUND;
}

static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data)
--
2.25.1