From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id EDE2FDDEBE for ; Sun, 25 Nov 2007 08:47:19 +1100 (EST) Date: Sun, 25 Nov 2007 00:47:08 +0300 From: Vitaly Bordug To: Jochen Friedrich Subject: Re: [RFC/PATCH] powerpc: Move CPM command handling into the cpm drivers Message-ID: <20071125004708.739366a1@kernel.crashing.org> In-Reply-To: <4748651E.2020806@scram.de> References: <4745BB5F.6060002@scram.de> <20071123005121.4d38d877@kernel.crashing.org> <4748651E.2020806@scram.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 24 Nov 2007 18:53:34 +0100 Jochen Friedrich wrote: > Hi Vitaly, > > >>> + printk(KERN_ERR "%s(): Not able to issue CPM command\n", > >>> + __FUNCTION__); > >>> + return -EIO; > >>> > >> Do these need to be protected with a spin lock? > >> > > Even that might be not enough - we may have simultaneous call of > > this func in non-smp case... I was thinking of some kind of > > refcount, so one that is going to issue CPM command, must do say > > pq_cpmp_get() and another driver won't be able to mangle with cpcr > > while it's not done with previous request. > > > > Yet I am not telling it was better the way it used to be - this > > approach looks okay but needs some efforts to defend against > > deadlocks while we are at it > > Wouldn't spin_lock_irqsave() prevent a deadlock? > yes, I believe it is OK for now. > Thanks, > Jochen -- Sincerely, Vitaly