On Wed, May 22, 2013 at 07:24:38PM +0200, Maarten Lankhorst wrote: > >> +- Functions to only acquire a single w/w mutex, which results in the > >> exact same > >> + semantics as a normal mutex. These functions have the _single postfix. > > This is missing rationale.
> trylock_single is useful when iterating over a list, and you want to evict a > bo, but only the first one that can be acquired. > lock_single is useful when only a single bo needs to be acquired, for example > to lock a buffer during mmap. OK, so given that its still early, monday and I haven't actually spend much time thinking on this; would it be possible to make: ww_mutex_lock(.ctx=NULL) act like ww_mutex_lock_single()? The idea is that if we don't provide a ctx, we'll get a different lockdep annotation; mutex_lock() vs mutex_lock_nest_lock(). So if we then go and make a mistake, lockdep should warn us. Would that work or should I stock up on morning juice?
