From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH 1/3] list_bl: Add hlist_bl_add_before/behind helpers Date: Thu, 28 Feb 2019 16:32:02 -0500 Message-ID: <20190228213201.GB23527@redhat.com> References: <20181220180651.4879-1-ntsironis@arrikto.com> <20181220180651.4879-2-ntsironis@arrikto.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181220180651.4879-2-ntsironis@arrikto.com> Sender: linux-kernel-owner@vger.kernel.org To: "Paul E. McKenney" , hch@infradead.org, Nikos Tsironis Cc: agk@redhat.com, dm-devel@redhat.com, mpatocka@redhat.com, iliastsi@arrikto.com, linux-kernel@vger.kernel.org List-Id: dm-devel.ids On Thu, Dec 20 2018 at 1:06pm -0500, Nikos Tsironis wrote: > Add hlist_bl_add_before/behind helpers to add an element before/after an > existing element in a bl_list. > > Signed-off-by: Nikos Tsironis > Signed-off-by: Ilias Tsitsimpis > --- > include/linux/list_bl.h | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > index 3fc2cc57ba1b..2fd918e5fd48 100644 > --- a/include/linux/list_bl.h > +++ b/include/linux/list_bl.h > @@ -86,6 +86,33 @@ static inline void hlist_bl_add_head(struct hlist_bl_node *n, > hlist_bl_set_first(h, n); > } > > +static inline void hlist_bl_add_before(struct hlist_bl_node *n, > + struct hlist_bl_node *next) > +{ > + struct hlist_bl_node **pprev = next->pprev; > + > + n->pprev = pprev; > + n->next = next; > + next->pprev = &n->next; > + > + /* pprev may be `first`, so be careful not to lose the lock bit */ > + WRITE_ONCE(*pprev, > + (struct hlist_bl_node *) > + ((unsigned long)n | > + ((unsigned long)*pprev & LIST_BL_LOCKMASK))); > +} > + > +static inline void hlist_bl_add_behind(struct hlist_bl_node *n, > + struct hlist_bl_node *prev) > +{ > + n->next = prev->next; > + n->pprev = &prev->next; > + WRITE_ONCE(prev->next, n); > + > + if (n->next) > + n->next->pprev = &n->next; > +} > + > static inline void __hlist_bl_del(struct hlist_bl_node *n) > { > struct hlist_bl_node *next = n->next; > -- > 2.11.0 Hi Paul and Christoph, You've added your Signed-off-by to include/linux/list_bl.h commits in the past. I'm not sure how this proposed patch should be handled. These new hlist_bl_add_{before,behind} changes are a prereq for dm-snapshot changes that Nikos has proposed, please see: https://patchwork.kernel.org/patch/10739265/ Any assistance/review you, or others on LKML, might be able to provide would be appreciated. Thanks, Mike