Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 7 Oct 2019 20:47:54 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Arvind Sankar <nivedita@alum.mit.edu>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Christoph Hellwig <hch@lst.de>, linux-kernel@vger.kernel.org
Subject: Re: ehci-pci breakage with dma-mapping changes in 5.4-rc2
Message-ID: <20191007184754.GB31345@lst.de>
References: <20191007022454.GA5270@rani.riverdale.lan> <20191007073448.GA882@lst.de> <20191007175430.GA32537@rani.riverdale.lan> <20191007175528.GA21857@lst.de> <20191007175630.GA28861@infradead.org> <20191007175856.GA42018@rani.riverdale.lan> <20191007183206.GA13589@rani.riverdale.lan>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20191007183206.GA13589@rani.riverdale.lan>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Oct 07, 2019 at 02:32:07PM -0400, Arvind Sankar wrote:
> On Mon, Oct 07, 2019 at 01:58:57PM -0400, Arvind Sankar wrote:
> > On Mon, Oct 07, 2019 at 10:56:30AM -0700, Christoph Hellwig wrote:
> > > On Mon, Oct 07, 2019 at 07:55:28PM +0200, Christoph Hellwig wrote:
> > > > On Mon, Oct 07, 2019 at 01:54:32PM -0400, Arvind Sankar wrote:
> > > > > It doesn't boot with the patch. Won't it go
> > > > > 	dma_get_required_mask
> > > > > 	-> intel_get_required_mask
> > > > > 	-> iommu_need_mapping
> > > > > 	-> dma_get_required_mask
> > > > > ?
> > > > > 
> > > > > Should the call to dma_get_required_mask in iommu_need_mapping be
> > > > > replaced with dma_direct_get_required_mask on top of your patch?
> > > > 
> > > > Yes, sorry.
> > > 
> > > Actually my patch already calls dma_direct_get_required_mask.
> > > How did you get the loop?
> > 
> > The function iommu_need_mapping (not changed by your patch) calls
> > dma_get_required_mask internally, to check whether the device's dma_mask
> > is big enough or not. That's the call I was asking whether it needs to
> > be changed.
> 
> Yeah the attached patch seems to fix it.

That looks fine to me:

Acked-by: Christoph Hellwig <hch@lst.de>