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[media] dvb-frontends: Don't use dynamic static allocation

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Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
	drivers/media/dvb-frontends/bcm3510.c:230:1: warning: 'bcm3510_do_hab_cmd' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/itd1000.c:69:1: warning: 'itd1000_write_regs.constprop.0' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/mt312.c:126:1: warning: 'mt312_write' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/nxt200x.c:111:1: warning: 'nxt200x_writebytes' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/stb6100.c:216:1: warning: 'stb6100_write_reg_range.constprop.3' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/stv6110.c:98:1: warning: 'stv6110_write_regs' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/stv6110x.c:85:1: warning: 'stv6110x_write_regs' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/tda18271c2dd.c:147:1: warning: 'WriteRegs' uses dynamic stack allocation [enabled by default]
	drivers/media/dvb-frontends/zl10039.c:119:1: warning: 'zl10039_write' 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>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Mauro Carvalho Chehab
2013-11-02 05:05:18 -03:00
parent 9736a89daf
commit 8393796dfa
9 changed files with 101 additions and 10 deletions
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12
drivers/media/dvb-frontends/zl10039.c
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@@ -30,6 +30,9 @@
static int debug;
/* Max transfer size done by I2C transfer functions */
#define MAX_XFER_SIZE 64
#define dprintk(args...) \
do { \
if (debug) \
@@ -98,7 +101,7 @@ static int zl10039_write(struct zl10039_state *state,
const enum zl10039_reg_addr reg, const u8 *src,
const size_t count)
{
u8 buf[count + 1];
u8 buf[MAX_XFER_SIZE];
struct i2c_msg msg = {
.addr = state->i2c_addr,
.flags = 0,
@@ -106,6 +109,13 @@ static int zl10039_write(struct zl10039_state *state,
.len = count + 1,
};
if (1 + count > sizeof(buf)) {
printk(KERN_WARNING
"%s: i2c wr reg=%04x: len=%zd is too big!\n",
KBUILD_MODNAME, reg, count);
return -EINVAL;
}
dprintk("%s\n", __func__);
/* Write register address and data in one go */
buf[0] = reg;