Re: modinfo <modulename> question

[Randy Dunlap <randy.dunlap@oracle.com>]

On Wed, 5 Sep 2007 12:34:13 -0400 (EDT) Justin Piszcz wrote:

> Is there anyway to get/see what parameters were passed to a kernel module? 
> Running modinfo -p <module> will show the defaults, but for example, st, 
> the scsi tape driver, is there a way to see what it is currently using? I 
> know in dmesg it shows this when you load it initially (but if say dmesg 
> has been cleared or the buffer was filled up)?

If a "module" (whether built as a loadable module or builtin to the
kernel image) uses module_param() with a permission (or mode) field
that allows reading that parameter, then the parameter will show up
in /sys/module/<module>/parameters/<parameter>.

E.g., drivers/scsi/sg has these parameters listed and are readable
by anyone:

-rw-r--r-- 1 root root 4096 Sep  5 10:07 allow_dio
-rw-r--r-- 1 root root 4096 Sep  5 10:07 def_reserved_size
-rw-r--r-- 1 root root 4096 Sep  5 10:07 scatter_elem_sz

However, the st driver uses 0 for permission (mode), so none of its
parameters is visible.

---
~Randy
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