media: dvb-usb: Constify struct i2c_algorithm

'struct i2c_algorithm' are not modified in these drivers.

Constifying this structure moves some data to a read-only section, so
increase overall security, especially when the structure holds some
function pointers.

More over, dvb_usb_device_properties->i2c_algo seems to only be copied in
i2c_adapter->algo, which is already a "const struct i2c_algorithm".
This is done in dvb_usb_i2c_init()

On a x86_64, with allmodconfig, as an example:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  30571	   5916	     36	  36523	   8eab	drivers/media/usb/dvb-usb/af9005.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  30667	   5852	     36	  36555	   8ecb	drivers/media/usb/dvb-usb/af9005.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

drivers/media/usb/dvb-usb/af9005.c

@@ -445,7 +445,7 @@ static u32 af9005_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm af9005_i2c_algo = {
+static const struct i2c_algorithm af9005_i2c_algo = {
 	.master_xfer = af9005_i2c_xfer,
 	.functionality = af9005_i2c_func,
 };

drivers/media/usb/dvb-usb/az6027.c

@@ -1062,7 +1062,7 @@ static u32 az6027_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm az6027_i2c_algo = {
+static const struct i2c_algorithm az6027_i2c_algo = {
 	.master_xfer   = az6027_i2c_xfer,
 	.functionality = az6027_i2c_func,
 };

drivers/media/usb/dvb-usb/cxusb.c

@@ -287,7 +287,7 @@ static u32 cxusb_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }
 
-static struct i2c_algorithm cxusb_i2c_algo = {
+static const struct i2c_algorithm cxusb_i2c_algo = {
 	.master_xfer   = cxusb_i2c_xfer,
 	.functionality = cxusb_i2c_func,
 };

drivers/media/usb/dvb-usb/digitv.c

@@ -88,7 +88,7 @@ static u32 digitv_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm digitv_i2c_algo = {
+static const struct i2c_algorithm digitv_i2c_algo = {
 	.master_xfer   = digitv_i2c_xfer,
 	.functionality = digitv_i2c_func,
 };

drivers/media/usb/dvb-usb/dtv5100.c

@@ -97,7 +97,7 @@ static u32 dtv5100_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm dtv5100_i2c_algo = {
+static const struct i2c_algorithm dtv5100_i2c_algo = {
 	.master_xfer   = dtv5100_i2c_xfer,
 	.functionality = dtv5100_i2c_func,
 };

drivers/media/usb/dvb-usb/dvb-usb.h

@@ -309,7 +309,7 @@ struct dvb_usb_device_properties {
 		struct dvb_rc core;
 	} rc;
 
-	struct i2c_algorithm *i2c_algo;
+	const struct i2c_algorithm *i2c_algo;
 
 	int generic_bulk_ctrl_endpoint;
 	int generic_bulk_ctrl_endpoint_response;

drivers/media/usb/dvb-usb/dw2102.c

@@ -839,37 +839,37 @@ static u32 dw210x_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm dw2102_i2c_algo = {
+static const struct i2c_algorithm dw2102_i2c_algo = {
 	.master_xfer = dw2102_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm dw2102_serit_i2c_algo = {
+static const struct i2c_algorithm dw2102_serit_i2c_algo = {
 	.master_xfer = dw2102_serit_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm dw2102_earda_i2c_algo = {
+static const struct i2c_algorithm dw2102_earda_i2c_algo = {
 	.master_xfer = dw2102_earda_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm dw2104_i2c_algo = {
+static const struct i2c_algorithm dw2104_i2c_algo = {
 	.master_xfer = dw2104_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm dw3101_i2c_algo = {
+static const struct i2c_algorithm dw3101_i2c_algo = {
 	.master_xfer = dw3101_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm s6x0_i2c_algo = {
+static const struct i2c_algorithm s6x0_i2c_algo = {
 	.master_xfer = s6x0_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };
 
-static struct i2c_algorithm su3000_i2c_algo = {
+static const struct i2c_algorithm su3000_i2c_algo = {
 	.master_xfer = su3000_i2c_transfer,
 	.functionality = dw210x_i2c_func,
 };

drivers/media/usb/dvb-usb/m920x.c

@@ -319,7 +319,7 @@ static u32 m920x_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm m920x_i2c_algo = {
+static const struct i2c_algorithm m920x_i2c_algo = {
 	.master_xfer   = m920x_i2c_xfer,
 	.functionality = m920x_i2c_func,
 };

drivers/media/usb/dvb-usb/opera1.c

@@ -155,7 +155,7 @@ static u32 opera1_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm opera1_i2c_algo = {
+static const struct i2c_algorithm opera1_i2c_algo = {
 	.master_xfer = opera1_i2c_xfer,
 	.functionality = opera1_i2c_func,
 };

drivers/media/usb/dvb-usb/pctv452e.c

@@ -906,7 +906,7 @@ static struct stb6100_config stb6100_config = {
 };
 
 
-static struct i2c_algorithm pctv452e_i2c_algo = {
+static const struct i2c_algorithm pctv452e_i2c_algo = {
 	.master_xfer   = pctv452e_i2c_xfer,
 	.functionality = pctv452e_i2c_func
 };

drivers/media/usb/dvb-usb/technisat-usb2.c

@@ -199,7 +199,7 @@ static u32 technisat_usb2_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm technisat_usb2_i2c_algo = {
+static const struct i2c_algorithm technisat_usb2_i2c_algo = {
 	.master_xfer   = technisat_usb2_i2c_xfer,
 	.functionality = technisat_usb2_i2c_func,
 };

drivers/media/usb/dvb-usb/ttusb2.c

@@ -434,7 +434,7 @@ static u32 ttusb2_i2c_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_I2C;
 }
 
-static struct i2c_algorithm ttusb2_i2c_algo = {
+static const struct i2c_algorithm ttusb2_i2c_algo = {
 	.master_xfer   = ttusb2_i2c_xfer,
 	.functionality = ttusb2_i2c_func,
 };