linux-kernel - Re: [PATCH] staging: pi433: reduce stack size in tx thread

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Date:   Wed, 2 Aug 2017 10:20:38 +0200
From:   "Wolf Entwicklungen" <Marcus.Wolf@...f-Entwicklungen.de>
To:     "Arnd Bergmann" <arnd@...db.de>
Cc:     "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "Marcus Wolf" <linux@...f-entwicklungen.de>,
        "Arnd Bergmann" <arnd@...db.de>,
        "Joseph Wright" <rjosephwright@...il.com>,
        "dan.carpenter@...cle.com" <dan.carpenter@...cle.com>,
        "Derek Robson" <robsonde@...il.com>,
        "Colin Ian King" <colin.king@...onical.com>,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] staging: pi433: reduce stack size in tx thread

Reviewed-by: Marcus Wolf <linux@...f-entwicklungen.de>

Maybe tx_buffer is a bit more clearly then buffer.

Thanks,

Marcus

Am Mo, 31.07.2017, 10:57 schrieb Arnd Bergmann:
> Putting a 900 byte array on the stack is a clearly too much in the
> kernel, and sometimes results in warnings like:
>
> drivers/staging/pi433/pi433_if.c: In function 'pi433_tx_thread':
> drivers/staging/pi433/pi433_if.c:645:1: error: the frame size of 1028 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>
> This moves the buffer into the dynamically allocated per-device
> structure.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/staging/pi433/pi433_if.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
> index ed737f4b1e77..ec9811ae4735 100644
> --- a/drivers/staging/pi433/pi433_if.c
> +++ b/drivers/staging/pi433/pi433_if.c
> @@ -92,6 +92,7 @@ struct pi433_device {
>  	struct task_struct	*tx_task_struct;
>  	wait_queue_head_t	tx_wait_queue;
>  	u8			free_in_fifo;
> +	char			buffer[MAX_MSG_SIZE];
>
>  	/* rx related values */
>  	struct pi433_rx_cfg	rx_cfg;
> @@ -471,7 +472,7 @@ pi433_tx_thread(void *data)
>  	struct pi433_device *device = data;
>  	struct spi_device *spi = device->spi; /* needed for SET_CHECKED */
>  	struct pi433_tx_cfg tx_cfg;
> -	u8     buffer[MAX_MSG_SIZE];
> +	u8     *buffer = device->buffer;
>  	size_t size;
>  	bool   rx_interrupted = false;
>  	int    position, repetitions;
> --
> 2.9.0
>
>
>