diff options
| author | Mauro Carvalho Chehab <m.chehab@samsung.com> | 2013-11-02 05:11:47 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-04 10:57:33 -0800 |
| commit | 10184cdc523eb232ff416c6aa5819dfbcb681870 (patch) | |
| tree | 8ac84302e53179760d93bdd804c345e8c1261558 /drivers/media/dvb-frontends/af9013.c | |
| parent | 845b09830c162084301f65c947894389cd48e8b6 (diff) | |
media: dvb-frontends: Don't use dynamic static allocation
commit 37ebaf6891ee81687bb558e8375c0712d8264ed8 upstream.
Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/dvb-frontends/af9013.c:77:1: warning: 'af9013_wr_regs_i2c' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/af9033.c:188:1: warning: 'af9033_wr_reg_val_tab' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/af9033.c:68:1: warning: 'af9033_wr_regs' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/bcm3510.c:230:1: warning: 'bcm3510_do_hab_cmd' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/cxd2820r_core.c:84:1: warning: 'cxd2820r_rd_regs_i2c.isra.1' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/rtl2830.c:56:1: warning: 'rtl2830_wr' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/rtl2832.c:187:1: warning: 'rtl2832_wr' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/tda10071.c:52:1: warning: 'tda10071_wr_regs' uses dynamic stack allocation [enabled by default]
drivers/media/dvb-frontends/tda10071.c:84:1: warning: 'tda10071_rd_regs' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer. Considering that I2C
transfers are generally limited, and that devices used on USB has a
max data length of 64 bytes for the control URBs.
So, it seem safe to use 64 bytes as the hard limit for all those devices.
On most cases, the limit is a way lower than that, but this limit
is small enough to not affect the Kernel stack, and it is a no brain
limit, as using smaller ones would require to either carefully each
driver or to take a look on each datasheet.
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/media/dvb-frontends/af9013.c')
| -rw-r--r-- | drivers/media/dvb-frontends/af9013.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/media/dvb-frontends/af9013.c b/drivers/media/dvb-frontends/af9013.c index a204f282882..fb504f1e912 100644 --- a/drivers/media/dvb-frontends/af9013.c +++ b/drivers/media/dvb-frontends/af9013.c @@ -24,6 +24,9 @@ #include "af9013_priv.h" +/* Max transfer size done by I2C transfer functions */ +#define MAX_XFER_SIZE 64 + struct af9013_state { struct i2c_adapter *i2c; struct dvb_frontend fe; @@ -50,16 +53,23 @@ static int af9013_wr_regs_i2c(struct af9013_state *priv, u8 mbox, u16 reg, const u8 *val, int len) { int ret; - u8 buf[3+len]; + u8 buf[MAX_XFER_SIZE]; struct i2c_msg msg[1] = { { .addr = priv->config.i2c_addr, .flags = 0, - .len = sizeof(buf), + .len = 3 + len, .buf = buf, } }; + if (3 + len > sizeof(buf)) { + dev_warn(&priv->i2c->dev, + "%s: i2c wr reg=%04x: len=%d is too big!\n", + KBUILD_MODNAME, reg, len); + return -EINVAL; + } + buf[0] = (reg >> 8) & 0xff; buf[1] = (reg >> 0) & 0xff; buf[2] = mbox; |