module parameters

　　Parameter values can be assigned at load time by insmod or modprobe(this can read parameter from configuration file /etc/modeprobe.conf).

　　While you type the paras in command line, the paras should also be declared with the module_para marco in codes:

 static char *whom = "world";
 ;
 module_param(howmany, int, S_IRUGO);
 module_param(whom, charp, S_IRUGO);

The types of para are as following:

　　　　bool/invbool(true->false, false->true)

　　　　charp(a char pointer)

　　　　integer(int, long, short, uint, ulong, ushort)

　　　　array(values should be supplied as a comma-separated list)

The array parameter is declared in a different way:

 module_param_array(name,type,nump,perm);　　

　　Where name is the name of your array (and of the parameter), type is the type of thearray elements, nump is an integer variable, and perm is the usual permissions value. Ifthe array parameter is set at load time, nump is set to the number of values supplied.The module loader refuses to accept more values than will fit in the array.

　　TO define a type of para not defined above, see modulepara.h.

　　The final module_param fieldis a permission value, which is defiend in <linux/stat.h>. If perm is set to 0, there is no sysfs;otherwise, it appears under /sys/module with the givern set of permissions. Usually use S_IRUGO for those that only can be read. If you are read to detect the change of the paras and react, S_IRUGO| S_IWUSR would allow root to change the paras.