On Fri, Oct 19, 2007 at 09:50:14AM +0200, Jarek Poplawski wrote: > On Thu, Oct 18, 2007 at 07:48:19PM +0400, Oleg Nesterov wrote: > > On 10/18, Jarek Poplawski wrote: > > > > > > +/** > > > + * flush_work_sync - block until a work_struct's callback has terminated > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Hmm... > > > > > + * Similar to cancel_work_sync() but will only busy wait (without cancel) > > > + * if the work is queued. > > > > Yes, it won't block, but will spin in busy-wait loop until all other works > > scheduled before this work are finished. Not good. After that it really > > blocks waiting for this work to complete. > > > > And I am a bit confused. We can't use flush_workqueue() because some of the > > queued work_structs may take rtnl_lock, yes? But in that case we can't use > > the new flush_work_sync() helper as well, no?
OK, I know I'm dumber and dumber everyday, but it seems in a hurry I got it wrong again or miss something (as usual): these all flushes are rtnl lockup vulnerable wrt. other work functions, but cancel_work_sync looks perfectly fine... (Or am I wrong because: ...?) Then, if by any chance I'm right, something like flush_work_sync (or changed flush_scheduled_work, if there is no problem with such a change of implementation) could be safely (if it's called without locks used by flushed work only) done cancel_work_sync() way, by running a work function after try_to_grab_pending() returns 1 (after list_del_init - of course without respecting a queue order). Regards, Jarek P. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
