Re: brlock_is_locked()?

[Brad Chapman <kakadu_croc@yahoo.com>]

--- Jens Axboe <axboe@suse.de> wrote:
> On Wed, Aug 22 2001, Brad Chapman wrote:
> > >    (I checked the brlock code and didn't find any schedule()s; there's
> > >     probably a reason for that).
> > > 
> > > Ummm, this is SMP 101, you can't sleep with a lock held.
> > > The global kernel lock is special in this regard, but all
> > > other SMP locking primitives may not sleep.
> > 
> > 	Grrr....I read Rusty's Unreliable Guide to Kernel Locking (twice) and
> > still didn't remember that. Guess you have to schedule() yourself.
> 
> Errr, like Dave said, _you cannot sleep while holding a lock_. It's not
> just that the locking primitives themselves don't sleep, you must not
> call schedule() (or any other function that may block/sleep) while
> holding a lock. _That's_ SMP 101 :-)
> 
> -- 
> Jens Axboe

Mr. Axboe,

	Sorry, I was unclear in my statement. If we fail to grab the lock, 
_then_ we sleep. If we succeed, we work our butts off, give the lock up,
and then schedule(). No sleeping on the lock job ;-)

Brad 


=====
Brad Chapman

Permanent e-mail: kakadu_croc@yahoo.com
Current e-mail: kakadu@adelphia.net
Alternate e-mail: kakadu@netscape.net

__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/