diff mbox series

[-next,5/5] blk-iocost: read 'ioc->params' inside 'ioc->lock' in ioc_timer_fn()

Message ID 20221011083547.1831389-6-yukuai1@huaweicloud.com (mailing list archive)
State New, archived
Headers show
Series blk-iocost: some random patches to improve iocost | expand

Commit Message

Yu Kuai Oct. 11, 2022, 8:35 a.m. UTC 
From: Yu Kuai <yukuai3@huawei.com>

'ioc->params' is updated in ioc_refresh_params(), which is proteced by
'ioc->lock', however, ioc_timer_fn() read params outside the lock.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 block/blk-iocost.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Tejun Heo Oct. 11, 2022, 5:01 p.m. UTC | #1 
On Tue, Oct 11, 2022 at 04:35:47PM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> 'ioc->params' is updated in ioc_refresh_params(), which is proteced by
> 'ioc->lock', however, ioc_timer_fn() read params outside the lock.
> 
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.
diff mbox series

Patch

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 32e7e416d67c..acb10ba49da9 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2203,8 +2203,8 @@  static void ioc_timer_fn(struct timer_list *timer)
 	LIST_HEAD(surpluses);
 	int nr_debtors, nr_shortages = 0, nr_lagging = 0;
 	u64 usage_us_sum = 0;
-	u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM];
-	u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];
+	u32 ppm_rthr;
+	u32 ppm_wthr;
 	u32 missed_ppm[2], rq_wait_pct;
 	u64 period_vtime;
 	int prev_busy_level;
@@ -2215,6 +2215,8 @@  static void ioc_timer_fn(struct timer_list *timer)
 	/* take care of active iocgs */
 	spin_lock_irq(&ioc->lock);
 
+	ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM];
+	ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];
 	ioc_now(ioc, &now);
 
 	period_vtime = now.vnow - ioc->period_at_vtime;