linux-kernel - RE: [PATCH v2 2/3] mei: vsc: Don't use sleeping condition in wait_event

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Date: Thu, 22 Feb 2024 04:30:57 +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 2/3] mei: vsc: Don't use sleeping condition in
 wait_event_timeout()

> From: Sakari Ailus <sakari.ailus@...ux.intel.com>
> 
> vsc_tp_wakeup_request() called wait_event_timeout() with
> gpiod_get_value_cansleep() which may sleep, and does so as the
> implementation is that of gpio-ljca.
> 
> Move the GPIO state check outside the call.
> 
> 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 | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/misc/mei/vsc-tp.c b/drivers/misc/mei/vsc-tp.c index
> 2b69ada9349e..7b678005652b 100644
> --- a/drivers/misc/mei/vsc-tp.c
> +++ b/drivers/misc/mei/vsc-tp.c
> @@ -25,7 +25,8 @@
>  #define VSC_TP_ROM_BOOTUP_DELAY_MS		10
>  #define VSC_TP_ROM_XFER_POLL_TIMEOUT_US		(500 *
> USEC_PER_MSEC)
>  #define VSC_TP_ROM_XFER_POLL_DELAY_US		(20 *
> USEC_PER_MSEC)
> -#define VSC_TP_WAIT_FW_ASSERTED_TIMEOUT		(2 * HZ)
> +#define VSC_TP_WAIT_FW_POLL_TIMEOUT		(2 * HZ)
> +#define VSC_TP_WAIT_FW_POLL_DELAY_US		(20 *
> USEC_PER_MSEC)
>  #define VSC_TP_MAX_XFER_COUNT			5
> 
>  #define VSC_TP_PACKET_SYNC			0x31
> @@ -101,13 +102,15 @@ static int vsc_tp_wakeup_request(struct vsc_tp *tp)
>  	gpiod_set_value_cansleep(tp->wakeupfw, 0);
> 
>  	ret = wait_event_timeout(tp->xfer_wait,
> -				 atomic_read(&tp->assert_cnt) &&
> -				 gpiod_get_value_cansleep(tp->wakeuphost),
> -				 VSC_TP_WAIT_FW_ASSERTED_TIMEOUT);
> +				 atomic_read(&tp->assert_cnt),
> +				 VSC_TP_WAIT_FW_POLL_TIMEOUT);
>  	if (!ret)
>  		return -ETIMEDOUT;
> 
> -	return 0;
> +	return read_poll_timeout(gpiod_get_value_cansleep, ret, ret,
> +				 VSC_TP_WAIT_FW_POLL_DELAY_US,
> +				 VSC_TP_WAIT_FW_POLL_TIMEOUT, false,
> +				 tp->wakeuphost);
>  }
> 
>  static void vsc_tp_wakeup_release(struct vsc_tp *tp)
> --
> 2.39.2