On Fri, Jun 02, 2006 at 05:50:21AM +0100, Ricardo Correia wrote: > On Friday 02 June 2006 05:12, Neil Perrin wrote: > > I believe RW_LOCK_HELD checks it's not held by the calling thread only. > > Note, a thread should not doubly read lock the same lock as > > a write lock from another thread between the 2 would deadlock. > > Ok, that makes sense. Thanks :) > > I'm assuming RW_WRITE_HELD() and MUTEX_HELD() also only checks if it's held > by > the calling thread (I couldn't find any documentation on this, and the > implementation of the RW_xxx_HELD() macros weren't very easy to > understand :p)
Our userland threads library keeps track, of which reader locks are held by a given thread. If you look at the implementation of _rw_read_held(): http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/port/threads/rwlock.c#_rw_read_held it checks the current thread's list of locks to verify that it is not being held. > Oh well... now I only have to figure out a way to emulate this with POSIX > threads.. :) It's much easier with help from the implementation; you could just disable that single assert. Cheers, - jonathan -- Jonathan Adams, Solaris Kernel Development
