Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60046 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933942AbeFRQ7Q (ORCPT ); Mon, 18 Jun 2018 12:59:16 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5IGwrbh045928 for ; Mon, 18 Jun 2018 12:59:16 -0400 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jpfx8t431-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 18 Jun 2018 12:59:16 -0400 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 18 Jun 2018 12:59:14 -0400 Date: Mon, 18 Jun 2018 10:01:11 -0700 From: "Paul E. McKenney" To: NeilBrown Cc: Linus Torvalds , trondmy@hammerspace.com, Linux Kernel Mailing List , Linux NFS Mailing List Subject: Re: [PATCH] rculist: improve documentation for list_for_each_entry_from_rcu() Reply-To: paulmck@linux.vnet.ibm.com References: <20180613010427.GD3593@linux.vnet.ibm.com> <20180613013914.GE3593@linux.vnet.ibm.com> <87muvzihr8.fsf@notabene.neil.brown.name> <20180613100607.GH3593@linux.vnet.ibm.com> <874li0g1v3.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <874li0g1v3.fsf@notabene.neil.brown.name> Message-Id: <20180618170111.GB3593@linux.vnet.ibm.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Jun 18, 2018 at 02:22:40PM +1000, NeilBrown wrote: > > Unfortunately the patch for adding list_for_each_entry_from_rcu() > wasn't the final patch after all review. It is functionally > correct but the documentation was incomplete. > > This patch adds this missing documentation which includes an update to > the documentation for list_for_each_entry_continue_rcu() to match the > documentation for the new list_for_each_entry_from_rcu(), and adds > list_for_each_entry_from_rcu() and the already existing > hlist_for_each_entry_from_rcu() to section 7 of whatisRCU.txt. > > Reviewed-by: Paul E. McKenney > Signed-off-by: NeilBrown Once I rebase my commits to v4.18-rc1, I will apply this, thank you! (If you were wanting something else to happen with this patch, please let me know.) Thanx, Paul > --- > Documentation/RCU/whatisRCU.txt | 2 ++ > include/linux/rculist.h | 19 ++++++++++++++++++- > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt > index 65eb856526b7..d43524493fb3 100644 > --- a/Documentation/RCU/whatisRCU.txt > +++ b/Documentation/RCU/whatisRCU.txt > @@ -816,11 +816,13 @@ RCU list traversal: > list_next_rcu > list_for_each_entry_rcu > list_for_each_entry_continue_rcu > + list_for_each_entry_from_rcu > hlist_first_rcu > hlist_next_rcu > hlist_pprev_rcu > hlist_for_each_entry_rcu > hlist_for_each_entry_rcu_bh > + hlist_for_each_entry_from_rcu > hlist_for_each_entry_continue_rcu > hlist_for_each_entry_continue_rcu_bh > hlist_nulls_first_rcu > diff --git a/include/linux/rculist.h b/include/linux/rculist.h > index 36df6ccbc874..4786c2235b98 100644 > --- a/include/linux/rculist.h > +++ b/include/linux/rculist.h > @@ -396,7 +396,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, > * @member: the name of the list_head within the struct. > * > * Continue to iterate over list of given type, continuing after > - * the current position. > + * the current position which must have been in the list when the RCU read > + * lock was taken. > + * This would typically require either that you obtained the node from a > + * previous walk of the list in the same RCU read-side critical section, or > + * that you held some sort of non-RCU reference (such as a reference count) > + * to keep the node alive *and* in the list. > + * > + * This iterator is similar to list_for_each_entry_from_rcu() except > + * this starts after the given position and that one starts at the given > + * position. > */ > #define list_for_each_entry_continue_rcu(pos, head, member) \ > for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ > @@ -411,6 +420,14 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, > * > * Iterate over the tail of a list starting from a given position, > * which must have been in the list when the RCU read lock was taken. > + * This would typically require either that you obtained the node from a > + * previous walk of the list in the same RCU read-side critical section, or > + * that you held some sort of non-RCU reference (such as a reference count) > + * to keep the node alive *and* in the list. > + * > + * This iterator is similar to list_for_each_entry_continue_rcu() except > + * this starts from the given position and that one starts from the position > + * after the given position. > */ > #define list_for_each_entry_from_rcu(pos, head, member) \ > for (; &(pos)->member != (head); \ > -- > 2.14.0.rc0.dirty >