From 89850fce16a1a75caacca77cfa0c829aeea4f886 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 10 Aug 2021 15:11:51 -0600
Subject: [PATCH] io_uring: run timeouts from task_work
Git-commit: 89850fce16a1a75caacca77cfa0c829aeea4f886
Patch-mainline: v5.15-rc1
References: bsc#1199011
This is in preparation to making the completion lock work outside of
hard/soft IRQ context.
Add a timeout_lock to handle the ordering of timeout completions or
cancelations with the timeouts actually triggering.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: David Disseldorp <ddiss@suse.de>
---
fs/io_uring.c | 54 ++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 40 insertions(+), 14 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 64241e2d3dd9..b8d09565d3ba 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -409,6 +409,8 @@ struct io_ring_ctx {
struct {
spinlock_t completion_lock;
+ spinlock_t timeout_lock;
+
/*
* ->iopoll_list is protected by the ctx->uring_lock for
* io_uring instances that don't use IORING_SETUP_SQPOLL.
@@ -1188,6 +1190,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->cq_wait);
spin_lock_init(&ctx->completion_lock);
+ spin_lock_init(&ctx->timeout_lock);
INIT_LIST_HEAD(&ctx->iopoll_list);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
@@ -1328,6 +1331,7 @@ static void io_queue_async_work(struct io_kiocb *req)
static void io_kill_timeout(struct io_kiocb *req, int status)
__must_hold(&req->ctx->completion_lock)
+ __must_hold(&req->ctx->timeout_lock)
{
struct io_timeout_data *io = req->async_data;
@@ -1355,9 +1359,12 @@ static void io_queue_deferred(struct io_ring_ctx *ctx)
}
static void io_flush_timeouts(struct io_ring_ctx *ctx)
+ __must_hold(&ctx->completion_lock)
{
u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+ unsigned long flags;
+ spin_lock_irqsave(&ctx->timeout_lock, flags);
while (!list_empty(&ctx->timeout_list)) {
u32 events_needed, events_got;
struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
@@ -1382,6 +1389,7 @@ static void io_flush_timeouts(struct io_ring_ctx *ctx)
io_kill_timeout(req, 0);
}
ctx->cq_last_tm_flush = seq;
+ spin_unlock_irqrestore(&ctx->timeout_lock, flags);
}
static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
@@ -5455,6 +5463,20 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
return 0;
}
+static void io_req_task_timeout(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ spin_lock_irq(&ctx->completion_lock);
+ io_cqring_fill_event(ctx, req->user_data, -ETIME, 0);
+ io_commit_cqring(ctx);
+ spin_unlock_irq(&ctx->completion_lock);
+
+ io_cqring_ev_posted(ctx);
+ req_set_fail(req);
+ io_put_req(req);
+}
+
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
@@ -5463,24 +5485,20 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
- spin_lock_irqsave(&ctx->completion_lock, flags);
+ spin_lock_irqsave(&ctx->timeout_lock, flags);
list_del_init(&req->timeout.list);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
+ spin_unlock_irqrestore(&ctx->timeout_lock, flags);
- io_cqring_fill_event(ctx, req->user_data, -ETIME, 0);
- io_commit_cqring(ctx);
- spin_unlock_irqrestore(&ctx->completion_lock, flags);
-
- io_cqring_ev_posted(ctx);
- req_set_fail(req);
- io_put_req(req);
+ req->io_task_work.func = io_req_task_timeout;
+ io_req_task_work_add(req);
return HRTIMER_NORESTART;
}
static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
__u64 user_data)
- __must_hold(&ctx->completion_lock)
+ __must_hold(&ctx->timeout_lock)
{
struct io_timeout_data *io;
struct io_kiocb *req;
@@ -5502,7 +5520,7 @@ static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
}
static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
- __must_hold(&ctx->completion_lock)
+ __must_hold(&ctx->timeout_lock)
{
struct io_kiocb *req = io_timeout_extract(ctx, user_data);
@@ -5517,7 +5535,7 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
struct timespec64 *ts, enum hrtimer_mode mode)
- __must_hold(&ctx->completion_lock)
+ __must_hold(&ctx->timeout_lock)
{
struct io_kiocb *req = io_timeout_extract(ctx, user_data);
struct io_timeout_data *data;
@@ -5576,13 +5594,15 @@ static int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
struct io_ring_ctx *ctx = req->ctx;
int ret;
- spin_lock_irq(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
if (!(req->timeout_rem.flags & IORING_TIMEOUT_UPDATE))
ret = io_timeout_cancel(ctx, tr->addr);
else
ret = io_timeout_update(ctx, tr->addr, &tr->ts,
io_translate_timeout_mode(tr->flags));
+ spin_unlock_irq(&ctx->timeout_lock);
+ spin_lock_irq(&ctx->completion_lock);
io_cqring_fill_event(ctx, req->user_data, ret, 0);
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
@@ -5637,7 +5657,7 @@ static int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
struct list_head *entry;
u32 tail, off = req->timeout.off;
- spin_lock_irq(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
/*
* sqe->off holds how many events that need to occur for this
@@ -5676,7 +5696,7 @@ static int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
list_add(&req->timeout.list, entry);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
- spin_unlock_irq(&ctx->completion_lock);
+ spin_unlock_irq(&ctx->timeout_lock);
return 0;
}
@@ -5730,7 +5750,9 @@ static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
spin_lock_irqsave(&ctx->completion_lock, flags);
if (ret != -ENOENT)
goto done;
+ spin_lock(&ctx->timeout_lock);
ret = io_timeout_cancel(ctx, sqe_addr);
+ spin_unlock(&ctx->timeout_lock);
if (ret != -ENOENT)
goto done;
ret = io_poll_cancel(ctx, sqe_addr, false);
@@ -5772,7 +5794,9 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
spin_lock_irq(&ctx->completion_lock);
if (ret != -ENOENT)
goto done;
+ spin_lock(&ctx->timeout_lock);
ret = io_timeout_cancel(ctx, sqe_addr);
+ spin_unlock(&ctx->timeout_lock);
if (ret != -ENOENT)
goto done;
ret = io_poll_cancel(ctx, sqe_addr, false);
@@ -8801,12 +8825,14 @@ static bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
int canceled = 0;
spin_lock_irq(&ctx->completion_lock);
+ spin_lock(&ctx->timeout_lock);
list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
if (io_match_task(req, tsk, cancel_all)) {
io_kill_timeout(req, -ECANCELED);
canceled++;
}
}
+ spin_unlock(&ctx->timeout_lock);
if (canceled != 0)
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
--
2.34.1