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

From: Guenter Roeck
Date: Fri Apr 12 2013 - 17:30:25 EST

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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