From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] [IPV4]: Remove warning in node_set_parent. Date: Mon, 11 Feb 2008 11:48:49 -0800 Message-ID: <20080211114849.042a3da2@extreme> References: <1202719637-4925-1-git-send-email-den@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Cc: davem@davemloft.net, netdev@vger.kernel.org, devel@openvz.org, "Denis V. Lunev" To: "Denis V. Lunev" Return-path: Received: from mail.vyatta.com ([216.93.170.194]:34673 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756612AbYBKTs4 convert rfc822-to-8bit (ORCPT ); Mon, 11 Feb 2008 14:48:56 -0500 In-Reply-To: <1202719637-4925-1-git-send-email-den@openvz.org> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 11 Feb 2008 11:47:17 +0300 "Denis V. Lunev" wrote: > net/ipv4/fib_trie.c: In function 'node_set_parent': > net/ipv4/fib_trie.c:184: warning: assignment makes integer from pointer > without a cast > > Signed-off-by: Denis V. Lunev > --- > net/ipv4/fib_trie.c | 7 ++++--- > 1 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c > index f5fba3f..1753cd4 100644 > --- a/net/ipv4/fib_trie.c > +++ b/net/ipv4/fib_trie.c > @@ -177,10 +177,11 @@ static inline struct tnode *node_parent_rcu(struct node *node) > return rcu_dereference(ret); > } > > -static inline void node_set_parent(struct node *node, struct tnode *ptr) > +static inline void node_set_parent(struct node *node, struct tnode *__ptr) > { > - rcu_assign_pointer(node->parent, > - (unsigned long)ptr | NODE_TYPE(node)); > + struct node *ptr; > + ptr = (struct node *)((unsigned long)__ptr | NODE_TYPE(node)); > + rcu_assign_pointer(node->parent, ptr); > } > > static inline struct node *tnode_get_child(struct tnode *tn, unsigned int i) No, this causes new warning from assigning pointer (ptr) to integer node->parent. Why not just change rcupdate.h to do the right thing. >>From a00f7cbf1c2f2282eced236e1e8b99b0fecd213a Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 11 Feb 2008 11:28:13 -0800 Subject: [PATCH] eliminate warnings when rcu_assign_pointer is used with unsigned long It is reasonable to use RCU with non-pointer values, and describe the optimization. Signed-off-by: Stephen Hemminger --- include/linux/rcupdate.h | 13 +++++++------ 1 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 37a642c..c44ac87 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -172,14 +172,15 @@ struct rcu_head { * structure after the pointer assignment. More importantly, this * call documents which pointers will be dereferenced by RCU read-side * code. + * + * If value is the NULL (constant 0), then no barrier is needed. */ -#define rcu_assign_pointer(p, v) \ - ({ \ - if (!__builtin_constant_p(v) || \ - ((v) != NULL)) \ - smp_wmb(); \ - (p) = (v); \ +#define rcu_assign_pointer(p, v) \ + ({ \ + if (!(__builtin_constant_p(v) && v)) \ + smp_wmb(); \ + (p) = (v); \ }) /** -- 1.5.3.8 -- Stephen Hemminger