Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934200AbaKMURw (ORCPT ); Thu, 13 Nov 2014 15:17:52 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35400 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933296AbaKMURv (ORCPT ); Thu, 13 Nov 2014 15:17:51 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <1415906662-4576-17-git-send-email-bobby.prani@gmail.com> References: <1415906662-4576-17-git-send-email-bobby.prani@gmail.com> <1415906662-4576-1-git-send-email-bobby.prani@gmail.com> To: Pranith Kumar Cc: dhowells@redhat.com, "David S. Miller" , Dan Carpenter , netdev@vger.kernel.org (open list:NETWORKING [GENERAL]), linux-kernel@vger.kernel.org (open list), paulmck@linux.vnet.ibm.com Subject: Re: [PATCH 16/16] rxrpc: Replace smp_read_barrier_depends() with lockless_dereference() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <24349.1415909859.1@warthog.procyon.org.uk> Date: Thu, 13 Nov 2014 20:17:39 +0000 Message-ID: <24350.1415909859@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pranith Kumar wrote: > loop != call->acks_head || stop; > loop = (loop + 1) & (call->acks_winsz - 1) > ) { > - p_txb = call->acks_window + loop; > - smp_read_barrier_depends(); > + p_txb = lockless_dereference(call)->acks_window + loop; Nack. You've stuck an implicit barrier on a dereference that doesn't matter. And similar for other hunks of this patch. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/