V4L/DVB (12684): DVB: make DVB_MAX_ADAPTERS configurable

Support for more than 8 DVB devices is requested regularly so make it
a kconfig variable instead of a header define. Values in the range 4-32
are tested.

Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/Kconfig

@@ -2,6 +2,19 @@
 # DVB device configuration
 #
 
+config DVB_MAX_ADAPTERS
+	int "maximum number of DVB/ATSC adapters"
+	depends on DVB_CORE
+	default 8
+	range 1 255
+	help
+	  Maximum number of DVB/ATSC adapters. Increasing this number
+	  increases the memory consumption of the DVB subsystem even
+	  if a much lower number of DVB/ATSC adapters is present.
+	  Only values in the range 4-32 are tested.
+
+	  If you are unsure about this, use the default value 8
+
 config DVB_DYNAMIC_MINORS
 	bool "Dynamic DVB minor allocation"
 	depends on DVB_CORE

drivers/media/dvb/dvb-core/dvbdev.h

@@ -30,7 +30,12 @@
 
 #define DVB_MAJOR 212
 
+#if defined(CONFIG_DVB_MAX_ADAPTERS) && CONFIG_DVB_MAX_ADAPTERS > 0
+#define DVB_MAX_ADAPTERS CONFIG_DVB_MAX_ADAPTERS
+#else
+#warning invalid CONFIG_DVB_MAX_ADAPTERS value
 #define DVB_MAX_ADAPTERS 8
+#endif
 
 #define DVB_UNSET (-1)