[RFC PATCH] watchdog: Add hook for kicking in kdump path

Guenter Roeck linux at roeck-us.net
Fri Apr 12 17:30:24 EDT 2013

On Fri, Apr 12, 2013 at 05:16:27PM -0400, Don Zickus wrote:
> On Wed, Apr 10, 2013 at 08:10:41AM -0700, Guenter Roeck wrote:
> > > have no idea how to even find out if multiple watchdogs are open on the
> > > system.  Is there a list I could walk?  And with regard to 'watchdog is
> > 
> > /* the dev_t structure to store the dynamically allocated watchdog devices */
> > static dev_t watchdog_devt;
> > 
> > One way to look up the allocated watchdogs might be to loop through all kobj
> > instances for the major device using kobj_lookup. Don't know if there is a
> > better way.
> Hmm, I got around to poking at this today and I am not sure kobj_lookup
> will work.  Besides being surrounded with another mutex, I don't have
> access to the character device domain to pass to kobj_lookup.
> Perhaps I am not reading the code right, but I can't find a good way
> forward.
> The only other hack I can think of, is to embed a list object in the
> watchdog structure and list_add each new register'd watchdog.  Then it
> would be trivial to walk the watchdog list.
After looking into it again, I agree. Maybe you can give it a try. At least
other options look even more complicated (eg creating a watchdog class ?).


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