Miklos Szeredi <[email protected]> wrote: > > How about using cmpxchg? > > How? If the count is nonzero, an incremented count must be stored. > You can't do that atomically with cmpxchg. Yes you can. cmpxchg() is atomic. Several archs implement atomic_inc() and co with cmpxchg() or similar. Something like: static inline struct namespace *grab_namespace(struct namespace *n) { int old = atomic_read(&n->count); while (old > 0) { /* attempt to increment the counter */ old = cmpxchg(&n->count, old, old + 1); } return old > 0 ? n : NULL; } David - 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/
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