[PATCH 5.7 029/124] io-wq: add an option to cancel all matched reqs

Greg Kroah-Hartman
2020-08-24T08:40:02Z

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

[ Upstream commit 4f26bda1522c35d2701fc219368c7101c17005c1 ]

This adds support for cancelling all io-wq works matching a predicate.
It isn't used yet, so no change in observable behaviour.

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 | 60 +++++++++++++++++++++++++++++----------------------
fs/io-wq.h | 2 +-
fs/io_uring.c | 2 +-
3 files changed, 36 insertions(+), 28 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 3283f8c5b5a18..6d2e8ccc229e3 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -907,13 +907,15 @@ void io_wq_cancel_all(struct io_wq *wq)
struct io_cb_cancel_data {
work_cancel_fn *fn;
void *data;
+ int nr_running;
+ int nr_pending;
+ bool cancel_all;
};

static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
{
struct io_cb_cancel_data *match = data;
unsigned long flags;
- bool ret = false;

/*
* Hold the lock to avoid ->cur_work going out of scope, caller
@@ -924,55 +926,55 @@ static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
!(worker->cur_work->flags & IO_WQ_WORK_NO_CANCEL) &&
match->fn(worker->cur_work, match->data)) {
send_sig(SIGINT, worker->task, 1);
- ret = true;
+ match->nr_running++;
}
spin_unlock_irqrestore(&worker->lock, flags);

- return ret;
+ return match->nr_running && !match->cancel_all;
}

-static bool io_wqe_cancel_pending_work(struct io_wqe *wqe,
+static void 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;

+retry:
spin_lock_irqsave(&wqe->lock, flags);
wq_list_for_each(node, prev, &wqe->work_list) {
work = container_of(node, struct io_wq_work, list);
+ if (!match->fn(work, match->data))
+ continue;

- if (match->fn(work, match->data)) {
- wq_list_del(&wqe->work_list, node, prev);
- found = true;
- break;
- }
+ wq_list_del(&wqe->work_list, node, prev);
+ spin_unlock_irqrestore(&wqe->lock, flags);
+ io_run_cancel(work, wqe);
+ match->nr_pending++;
+ if (!match->cancel_all)
+ return;
+
+ /* not safe to continue after unlock */
+ goto retry;
}
spin_unlock_irqrestore(&wqe->lock, flags);
-
- if (found)
- io_run_cancel(work, wqe);
- return found;
}

-static bool io_wqe_cancel_running_work(struct io_wqe *wqe,
+static void io_wqe_cancel_running_work(struct io_wqe *wqe,
struct io_cb_cancel_data *match)
{
- bool found;
-
rcu_read_lock();
- found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
+ io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
rcu_read_unlock();
- return found;
}

enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
- void *data)
+ void *data, bool cancel_all)
{
struct io_cb_cancel_data match = {
- .fn = cancel,
- .data = data,
+ .fn = cancel,
+ .data = data,
+ .cancel_all = cancel_all,
};
int node;

@@ -984,7 +986,8 @@ enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];

- if (io_wqe_cancel_pending_work(wqe, &match))
+ io_wqe_cancel_pending_work(wqe, &match);
+ if (match.nr_pending && !match.cancel_all)
return IO_WQ_CANCEL_OK;
}

@@ -997,10 +1000,15 @@ enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];

- if (io_wqe_cancel_running_work(wqe, &match))
+ io_wqe_cancel_running_work(wqe, &match);
+ if (match.nr_running && !match.cancel_all)
return IO_WQ_CANCEL_RUNNING;
}

+ if (match.nr_running)
+ return IO_WQ_CANCEL_RUNNING;
+ if (match.nr_pending)
+ return IO_WQ_CANCEL_OK;
return IO_WQ_CANCEL_NOTFOUND;
}

@@ -1011,7 +1019,7 @@ static bool io_wq_io_cb_cancel_data(struct io_wq_work *work, void *data)

enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
{
- return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork);
+ return io_wq_cancel_cb(wq, io_wq_io_cb_cancel_data, (void *)cwork, false);
}

static bool io_wq_pid_match(struct io_wq_work *work, void *data)
@@ -1025,7 +1033,7 @@ enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid)
{
void *data = (void *) (unsigned long) pid;

- return io_wq_cancel_cb(wq, io_wq_pid_match, data);
+ return io_wq_cancel_cb(wq, io_wq_pid_match, data, false);
}

struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
diff --git a/fs/io-wq.h b/fs/io-wq.h
index 5ba12de7572f0..8902903831f25 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -134,7 +134,7 @@ enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid);
typedef bool (work_cancel_fn)(struct io_wq_work *, void *);

enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
- void *data);
+ void *data, bool cancel_all);

struct task_struct *io_wq_get_task(struct io_wq *wq);

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b33d4a97a8774..cf32705546773 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5023,7 +5023,7 @@ static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
enum io_wq_cancel cancel_ret;
int ret = 0;

- cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr);
+ cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr, false);
switch (cancel_ret) {
case IO_WQ_CANCEL_OK:
ret = 0;
--
2.25.1