From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761384AbXGXXIZ (ORCPT ); Tue, 24 Jul 2007 19:08:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755837AbXGXXIQ (ORCPT ); Tue, 24 Jul 2007 19:08:16 -0400 Received: from smtp105.sbc.mail.mud.yahoo.com ([68.142.198.204]:48120 "HELO smtp105.sbc.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754490AbXGXXIP (ORCPT ); Tue, 24 Jul 2007 19:08:15 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=CS+3TKn7y/cnJF1T4Nla1Y8DtqzreLucZvRDgyyGpU37ARMmPCjmJs+lUXSbwnonytpzYKoGYDiQ/pW1UD4e9rMjV6/iY8+UQRB27YSilZH4JfjY3CX7jvuE9ogg5tnWkxtLYTZAKSZZ2UFKXjsTp0mrkffyryx7hWZhInY3P1A= ; X-YMail-OSG: imWB7EEVM1kHvWfeLQ3hgzJXdbrbVBW_wzt5.2Bd8ktYWMBMsBAYgLR0iiX9cKnbHVRkH9ZOgQ-- From: David Brownell To: Russell King Subject: Re: [patch 2.6.23-rc1] dma_free_coherent() needs irqs enabled (sigh) Date: Tue, 24 Jul 2007 16:08:11 -0700 User-Agent: KMail/1.9.6 Cc: Linux Kernel list , David Miller References: <200707241429.05615.david-b@pacbell.net> <20070724220738.GD22165@flint.arm.linux.org.uk> In-Reply-To: <20070724220738.GD22165@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707241608.12198.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 24 July 2007, Russell King wrote: > On Tue, Jul 24, 2007 at 02:29:05PM -0700, David Brownell wrote: > > On at least ARM (and I'm told MIPS too) dma_free_coherent() has a newish > > call context requirement: unlike its dma_alloc_coherent() sibling, it > > may not be called with IRQs disabled. (This was new behavior on ARM as > > of late 2006, caused by ARM SMP updates.) > > I think you got the year wrong: > > 5edf71ae (Russell King 2005-11-25 15:52:51 +0000 364) WARN_ON(irqs_disabled()); > > which is due to this commit: > > [ARM] Do not call flush_tlb_kernel_range() with IRQs disabled. This little "to do" list item has been sitting in my mailbox way too long then. Certainly since it was fair to say "last year"! ;) Of course, 2.6.23-rc1 also merges all the gadget API updates I included to cope with this annoyance. So with any luck the issue will now finally have been properly whupped. > Signed-off-by: Russell King Thanks... > > Since it looks like that restriction won't be removed, this patch changes > > the definition of the API to include that requirement. > > The PCI DMA-mapping API had this restriction. For some reason, this > restriction was not carried forward into the DMA-API. Unfortunately > the restriction can not be removed without causing the problems > described in the commit which introduced it. Right, I noticed that. - Dave