From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikos Tsironis Subject: [PATCH 1/3] list_bl: Add hlist_bl_add_before/behind helpers Date: Thu, 20 Dec 2018 20:06:49 +0200 Message-ID: <20181220180651.4879-2-ntsironis@arrikto.com> References: <20181220180651.4879-1-ntsironis@arrikto.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181220180651.4879-1-ntsironis@arrikto.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: snitzer@redhat.com, agk@redhat.com, dm-devel@redhat.com Cc: mpatocka@redhat.com, iliastsi@arrikto.com List-Id: dm-devel.ids 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