On 04/05/2013 01:12 PM, Al Viro wrote:
@@ -635,22 +640,14 @@ struct dentry *dget_parent(struct dentry *dentry) { struct dentry *ret;-repeat: - /* - * Don't need rcu_dereference because we re-check it was correct under - * the lock. - */ rcu_read_lock(); - ret = dentry->d_parent; - spin_lock(&ret->d_lock); - if (unlikely(ret != dentry->d_parent)) { - spin_unlock(&ret->d_lock); - rcu_read_unlock(); - goto repeat; - } + ret = rcu_dereference(dentry->d_parent); rcu_read_unlock(); + if (dcount_inc_cmpxchg(ret)) + return ret; + spin_lock(&ret->d_lock);And WTF is going to protect your "ret" from being freed just as you'd done rcu_read_unlock()?
I think I had made a mistake here. I should move the rcu_read_unlock() down to before the return statement as well as after the spin_lock(). Thank for pointing this out. I will fix that in the next version. Anything else that needs to be fixed?
Regards, Longman -- 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/
