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Date:   Fri, 15 May 2020 12:07:18 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        Joerg Roedel <jroedel@suse.de>,
        linux-mediatek@lists.infradead.org
Subject: Re: [PATCH v2 23/33] iommu/mediatek-v1 Convert to
 probe/release_device() call-backs
Message-ID: <20200515100718.GS18353@8bytes.org>
References: <20200414131542.25608-1-joro@8bytes.org>
 <20200414131542.25608-24-joro@8bytes.org>
 <1589528699.26119.9.camel@mhfsdcap03>
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Hi,

On Fri, May 15, 2020 at 03:44:59PM +0800, Yong Wu wrote:
> On Tue, 2020-04-14 at 15:15 +0200, Joerg Roedel wrote:
> > -	return iommu_device_link(&data->iommu, dev);
> > +	err = arm_iommu_attach_device(dev, mtk_mapping);
> > +	if (err)
> > +		dev_err(dev, "Can't create IOMMU mapping - DMA-OPS will not work\n");
> 
> 
> Hi Joerg,
> 
>      Thanks very much for this patch.
> 
>      This arm_iommu_attach_device is called just as we expected.
> 
>      But it will fail in this callstack as the group->mutex was tried to
> be re-locked...
> 
> [<c0938e8c>] (iommu_attach_device) from [<c0317590>]
> (__arm_iommu_attach_device+0x34/0x90)
> [<c0317590>] (__arm_iommu_attach_device) from [<c03175f8>]
> (arm_iommu_attach_device+0xc/0x20)
> [<c03175f8>] (arm_iommu_attach_device) from [<c09432cc>]
> (mtk_iommu_probe_finalize+0x34/0x50)
> [<c09432cc>] (mtk_iommu_probe_finalize) from [<c093a8ac>]
> (bus_iommu_probe+0x2a8/0x2c4)
> [<c093a8ac>] (bus_iommu_probe) from [<c093a950>] (bus_set_iommu
> +0x88/0xd4)
> [<c093a950>] (bus_set_iommu) from [<c0943c74>] (mtk_iommu_probe
> +0x2f8/0x364)

Thanks for the report, is

	https://lore.kernel.org/lkml/1589530123-30240-1-git-send-email-yong.wu@mediatek.com/

The fix for this issue or is something else required?


Thanks,

	Joerg