Re: [PATCH v2 1/4] dcache: Don't take unnecessary lock in d_count update

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



> @@ -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()?
--
To unsubscribe from this list: send the line "unsubscribe autofs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Filesystem Development]     [Linux Ext4]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux