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

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Date:   Mon, 31 Jul 2017 10:57:47 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Marcus Wolf <linux@...f-Entwicklungen.de>
Cc:     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: [PATCH] staging: pi433: reduce stack size in tx thread

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