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[PATCHv2,24/29] dibusb-common: Don't use dynamic static allocation

Message ID 1383399097-11615-25-git-send-email-m.chehab@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab Nov. 2, 2013, 1:31 p.m. UTC 
Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:

	drivers/media/usb/dvb-usb/dibusb-common.c:124:1: warning: 'dibusb_i2c_msg' uses dynamic stack allocation [enabled by default]

Instead, let's enforce a limit for the buffer to be the max size of
a control URB payload data (80 bytes).

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
 drivers/media/usb/dvb-usb/dibusb-common.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/media/usb/dvb-usb/dibusb-common.c b/drivers/media/usb/dvb-usb/dibusb-common.c
index c2dded92f1d3..ae9eed810bc2 100644
--- a/drivers/media/usb/dvb-usb/dibusb-common.c
+++ b/drivers/media/usb/dvb-usb/dibusb-common.c
@@ -105,11 +105,16 @@  EXPORT_SYMBOL(dibusb2_0_power_ctrl);
 static int dibusb_i2c_msg(struct dvb_usb_device *d, u8 addr,
 			  u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
 {
-	u8 sndbuf[wlen+4]; /* lead(1) devaddr,direction(1) addr(2) data(wlen) (len(2) (when reading)) */
+	u8 sndbuf[80]; /* lead(1) devaddr,direction(1) addr(2) data(wlen) (len(2) (when reading)) */
 	/* write only ? */
 	int wo = (rbuf == NULL || rlen == 0),
 		len = 2 + wlen + (wo ? 0 : 2);
 
+	if (4 + wlen > sizeof(sndbuf)) {
+		warn("i2c wr: len=%d is too big!\n", wlen);
+		return -EREMOTEIO;
+	}
+
 	sndbuf[0] = wo ? DIBUSB_REQ_I2C_WRITE : DIBUSB_REQ_I2C_READ;
 	sndbuf[1] = (addr << 1) | (wo ? 0 : 1);