From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755236Ab2LMKsb (ORCPT ); Thu, 13 Dec 2012 05:48:31 -0500 Received: from smtp.eu.citrix.com ([46.33.159.39]:53306 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754848Ab2LMKsB (ORCPT ); Thu, 13 Dec 2012 05:48:01 -0500 X-IronPort-AV: E=Sophos;i="4.84,273,1355097600"; d="scan'208";a="110292" From: Roger Pau Monne To: CC: Roger Pau Monne , Huang Ying , Konrad Rzeszutek Wilk Subject: [PATCH v4 2/3] llist: add a safe version of llist_for_each_entry Date: Thu, 13 Dec 2012 11:39:38 +0100 Message-ID: <1355395179-55724-2-git-send-email-roger.pau@citrix.com> X-Mailer: git-send-email 1.7.7.5 (Apple Git-26) In-Reply-To: <1355395179-55724-1-git-send-email-roger.pau@citrix.com> References: <1355395179-55724-1-git-send-email-roger.pau@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Roger Pau Monné Cc: Huang Ying Cc: Konrad Rzeszutek Wilk --- Changes since v3: * Change n to use type *, to keep the same semantics as list_for_each_entry_safe. Changes since v2: * Allow to pass a NULL node as the first entry of deleted list entries. --- include/linux/llist.h | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/include/linux/llist.h b/include/linux/llist.h index a5199f6..f551ac4 100644 --- a/include/linux/llist.h +++ b/include/linux/llist.h @@ -125,6 +125,35 @@ static inline void init_llist_head(struct llist_head *list) (pos) = llist_entry((pos)->member.next, typeof(*(pos)), member)) /** + * llist_for_each_entry_safe - safely iterate over some deleted entries of + * lock-less list of given type + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @node: the fist entry of deleted list entries. + * @member: the name of the llist_node with the struct. + * + * In general, some entries of the lock-less list can be traversed + * safely only after being removed from list, so start with an entry + * instead of list head. + * + * If being used on entries deleted from lock-less list directly, the + * traverse order is from the newest to the oldest added entry. If + * you want to traverse from the oldest to the newest, you must + * reverse the order by yourself before traversing. + * + * n is used to store a reference to the next item llist_node, so + * pos can be freed while iterating. + */ +#define llist_for_each_entry_safe(pos, n, node, member) \ + for ((pos) = llist_entry((node), typeof(*(pos)), member), \ + (n) = llist_entry(((&(pos)->member != NULL) ? \ + (pos)->member.next : NULL), typeof(*(pos)), member); \ + &(pos)->member != NULL; \ + (pos) = n, \ + (n) = llist_entry(((&(pos)->member != NULL) ? \ + (pos)->member.next : NULL), typeof(*(pos)), member)) + +/** * llist_empty - tests whether a lock-less list is empty * @head: the list to test * -- 1.7.7.5 (Apple Git-26)