[PATCH 4/4] [media] mxl111sf: reduce stack usage in init function

From: Arnd Bergmann
Date: Thu Feb 02 2017 - 09:54:19 EST


mxl111sf uses a lot of kernel stack memory as it puts an i2c_client
structure on the stack:

drivers/media/usb/dvb-usb-v2/mxl111sf.c: In function 'mxl111sf_init':
drivers/media/usb/dvb-usb-v2/mxl111sf.c:953:1: error: the frame size of 1248 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]

We can avoid doing this by open-coding the call to i2c_transfer()
instead of calling tveeprom_read(), and not passing an i2c_client
pointer to tveeprom_hauppauge_analog(), which would ignore that
anyway.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/media/usb/dvb-usb-v2/mxl111sf.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index 80c635980526..60bc5cc9a483 100644
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -919,7 +919,12 @@ static int mxl111sf_init(struct dvb_usb_device *d)
struct mxl111sf_state *state = d_to_priv(d);
int ret;
static u8 eeprom[256];
- struct i2c_client c;
+ u8 reg = 0;
+ struct i2c_msg msg[2] = {
+ { .addr = 0xa0 >> 1, .len = 1, .buf = &reg },
+ { .addr = 0xa0 >> 1, .flags = I2C_M_RD,
+ .len = sizeof(eeprom), .buf = eeprom },
+ };

ret = get_chip_info(state);
if (mxl_fail(ret))
@@ -930,13 +935,10 @@ static int mxl111sf_init(struct dvb_usb_device *d)
if (state->chip_rev > MXL111SF_V6)
mxl111sf_config_pin_mux_modes(state, PIN_MUX_TS_SPI_IN_MODE_1);

- c.adapter = &d->i2c_adap;
- c.addr = 0xa0 >> 1;
-
- ret = tveeprom_read(&c, eeprom, sizeof(eeprom));
+ ret = i2c_transfer(&d->i2c_adap, msg, 2);
if (mxl_fail(ret))
return 0;
- tveeprom_hauppauge_analog(&c, &state->tv, (0x84 == eeprom[0xa0]) ?
+ tveeprom_hauppauge_analog(NULL, &state->tv, (0x84 == eeprom[0xa0]) ?
eeprom + 0xa0 : eeprom + 0x80);
#if 0
switch (state->tv.model) {
--
2.9.0