From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [patch 01/52] kernel: add bl_list Date: Tue, 29 Jun 2010 16:30:10 +1000 Message-ID: <20100629063010.GJ28364@laptop> References: <20100624030212.676457061@suse.de> <20100624030725.718438579@suse.de> <20100628213739.GF2357@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, John Stultz , Frank Mayhar To: "Paul E. McKenney" Return-path: Received: from cantor.suse.de ([195.135.220.2]:37299 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810Ab0F2Ga3 (ORCPT ); Tue, 29 Jun 2010 02:30:29 -0400 Content-Disposition: inline In-Reply-To: <20100628213739.GF2357@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, Jun 28, 2010 at 02:37:39PM -0700, Paul E. McKenney wrote: > On Thu, Jun 24, 2010 at 01:02:13PM +1000, npiggin@suse.de wrote: > > Introduce a type of hlist that can support the use of the lowest bit in the > > hlist_head. This will be subsequently used to implement per-bucket bit spinlock > > for inode and dentry hashes. > > > > Signed-off-by: Nick Piggin > > Looks good! One question on non-RCU pointer poisoning and a typo. > When these are addressed (perhaps by showing me the error of my ways): > > Reviewed-by: Paul E. McKenney > .. > > +static inline void hlist_bl_del(struct hlist_bl_node *n) > > +{ > > + __hlist_bl_del(n); > > + n->pprev = LIST_POISON2; > > OK, I'll bite... Why don't we poison the ->next pointer? Ah, I took the code from list_nulls.h, but actually, except for the hlist anchoring, the code is much more similar to the standard hlist. This can be poisoned, and I'll go through and look for other possible differences with hlists. > > +/** > > + * hlist_bl_del_init_rcu - deletes entry from hash list with re-initialization > > + * @n: the element to delete from the hash list. > > + * > > + * Note: hlist_bl_unhashed() on the node return true after this. It is > returns Yes, thanks!