linux-kernel - RE: [PATCH v2 1/3] mei: vsc: Call wake

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Date: Wed, 28 Feb 2024 08:19:04 +0000
From: "Wu, Wentong" <wentong.wu@...el.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
CC: Hans de Goede <hdegoede@...hat.com>, "Winkler, Tomas"
	<tomas.winkler@...el.com>, Arnd Bergmann <arnd@...db.de>, Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 1/3] mei: vsc: Call wake_up() in the threaded IRQ
 handler

> -----Original Message-----
> From: Sakari Ailus <sakari.ailus@...ux.intel.com>
>
> The hard IRQ handler vsc_tp_irq() is called with a raw spinlock taken.
> wake_up() acquires a spinlock, a sleeping lock on PREEMPT_RT. This leads to
> sleeping in atomic context.
> 
> Move the wake_up() call to the threaded IRQ handler vsc_tp_thread_isr()
> where it can be safely called.
> 
> Fixes: 566f5ca97680 ("mei: Add transport driver for IVSC device")
> Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>

Tested-and-Reviewed-by: Wentong Wu <wentong.wu@...el.com>
> ---
>  drivers/misc/mei/vsc-tp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/mei/vsc-tp.c b/drivers/misc/mei/vsc-tp.c index
> 6f4a4be6ccb5..2b69ada9349e 100644
> --- a/drivers/misc/mei/vsc-tp.c
> +++ b/drivers/misc/mei/vsc-tp.c
> @@ -416,8 +416,6 @@ static irqreturn_t vsc_tp_isr(int irq, void *data)
> 
>  	atomic_inc(&tp->assert_cnt);
> 
> -	wake_up(&tp->xfer_wait);
> -
>  	return IRQ_WAKE_THREAD;
>  }
> 
> @@ -425,6 +423,8 @@ static irqreturn_t vsc_tp_thread_isr(int irq, void
> *data)  {
>  	struct vsc_tp *tp = data;
> 
> +	wake_up(&tp->xfer_wait);
> +
>  	if (tp->event_notify)
>  		tp->event_notify(tp->event_notify_context);
> 
> --
> 2.39.2