2023-05-17 03:46:39

by Clark Wang

Subject: [PATCH] i3c: master: svc: fix cpu schedule in spin lock

pm_runtime_resume_and_get() may call sleep(). It cannot be used in
svc_i3c_master_start_xfer_locked(), because it is in a spin lock.

Move the pm runtime operations to svc_i3c_master_enqueue_xfer().

Signed-off-by: Clark Wang <[email protected]>
Fixes: 05be23ef78f7 ("i3c: master: svc: add runtime pm support")
---
drivers/i3c/master/svc-i3c-master.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index bca3a4352ad1..4edf33ed207d 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1096,12 +1096,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
if (!xfer)
return;

- ret = pm_runtime_resume_and_get(master->dev);
- if (ret < 0) {
- dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
- return;
- }
-
svc_i3c_master_clear_merrwarn(master);
svc_i3c_master_flush_fifo(master);

@@ -1116,9 +1110,6 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
break;
}

- pm_runtime_mark_last_busy(master->dev);
- pm_runtime_put_autosuspend(master->dev);
-
xfer->ret = ret;
complete(&xfer->comp);

@@ -1139,6 +1130,13 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
struct svc_i3c_xfer *xfer)
{
unsigned long flags;
+ int ret;
+
+ ret = pm_runtime_resume_and_get(master->dev);
+ if (ret < 0) {
+ dev_err(master->dev, "<%s> Cannot get runtime PM.\n", __func__);
+ return;
+ }

init_completion(&xfer->comp);
spin_lock_irqsave(&master->xferqueue.lock, flags);
@@ -1149,6 +1147,9 @@ static void svc_i3c_master_enqueue_xfer(struct svc_i3c_master *master,
svc_i3c_master_start_xfer_locked(master);
}
spin_unlock_irqrestore(&master->xferqueue.lock, flags);
+
+ pm_runtime_mark_last_busy(master->dev);
+ pm_runtime_put_autosuspend(master->dev);
}

static bool
--
2.34.1

2023-05-22 08:37:24

by Miquel Raynal

Subject: Re: [PATCH] i3c: master: svc: fix cpu schedule in spin lock

Hi Clark,

[email protected] wrote on Wed, 17 May 2023 11:30:29 +0800:

> pm_runtime_resume_and_get() may call sleep(). It cannot be used in
> svc_i3c_master_start_xfer_locked(), because it is in a spin lock.
>
> Move the pm runtime operations to svc_i3c_master_enqueue_xfer().
>
> Signed-off-by: Clark Wang <[email protected]>
> Fixes: 05be23ef78f7 ("i3c: master: svc: add runtime pm support")

Reviewed-by: Miquel Raynal <[email protected]>

Thanks,
Miquèl

2023-06-04 23:32:02

by Alexandre Belloni

Subject: Re: (subset) [PATCH] i3c: master: svc: fix cpu schedule in spin lock

On Wed, 17 May 2023 11:30:29 +0800, Clark Wang wrote:
> pm_runtime_resume_and_get() may call sleep(). It cannot be used in
> svc_i3c_master_start_xfer_locked(), because it is in a spin lock.
>
> Move the pm runtime operations to svc_i3c_master_enqueue_xfer().
>
>

Applied, thanks!

[1/1] i3c: master: svc: fix cpu schedule in spin lock
commit: 33beadb3b1ab74e69db2c49d9663f3a93a273943

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com