Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422641AbXAER0Q (ORCPT ); Fri, 5 Jan 2007 12:26:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422644AbXAER0P (ORCPT ); Fri, 5 Jan 2007 12:26:15 -0500 Received: from mailgw4.ericsson.se ([193.180.251.62]:33770 "EHLO mailgw4.ericsson.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422640AbXAER0O (ORCPT ); Fri, 5 Jan 2007 12:26:14 -0500 Message-ID: <459E896C.4050309@ericsson.com> Date: Fri, 05 Jan 2007 17:22:52 +0000 From: Jon Maloy User-Agent: Mozilla Thunderbird 0.9 (X11/20041127) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jarek Poplawski CC: Eric Sesterhenn , Per Liden , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "'tipc-discussion@lists.sourceforge.net'" Subject: Re: [PATCH] tipc: checking returns and Re: Possible Circular Locking in TIPC References: <20061228121702.GA5076@ff.dom.local> <459C396B.1090508@ericsson.com> <20070104122843.GC3175@ff.dom.local> <459D2854.1000405@ericsson.com> <20070105075857.GB1675@ff.dom.local> In-Reply-To: <20070105075857.GB1675@ff.dom.local> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 05 Jan 2007 17:23:26.0116 (UTC) FILETIME=[357E2E40:01C730EE] X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1584 Lines: 48 Jarek Poplawski wrote: > >If you are sure there is no circular locking possible >between these two functions and this entry->lock here >isn't endangered by other functions, you could try to >make lockdep "silent" like this: > > > write_lock_bh(&ref_table_lock); > if (tipc_ref_table.first_free) { > index = tipc_ref_table.first_free; > entry = &(tipc_ref_table.entries[index]); > index_mask = tipc_ref_table.index_mask; > /* take lock in case a previous user of entry still holds it */ > >- spin_lock_bh(&entry->lock, ); >+ local_bh_disable(); >+ spin_lock_nested(&entry->lock, SINGLE_DEPTH_NESTING); > > next_plus_upper = entry->data.next_plus_upper; > tipc_ref_table.first_free = next_plus_upper & index_mask; > reference = (next_plus_upper & ~index_mask) + index; > entry->data.reference = reference; > entry->object = object; > if (lock != 0) > *lock = &entry->lock; > >/* may stay as is or: */ >- spin_unlock_bh(&entry->lock); >+ spin_unlock(&entry->lock); >+ local_bh_enable(); > > } > write_unlock_bh(&ref_table_lock); > > > > Looks like an acceptable solution. I will try this. Thanks ///Jon - 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/