From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lu Baolu <baolu.lu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Subject: Re: [PATCH v2 13/33] iommu: Export bus_iommu_probe() and make is safe
 for re-probing
Date: Wed, 15 Apr 2020 14:10:03 +0800
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To: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>, Will Deacon <will-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>, Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Kukjin Kim <kgene-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Krzysztof Kozlowski <krzk-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Andy Gross <agross-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Bjorn Andersson <bjorn.andersson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>, Gerald Schaefer <gerald.schaefer-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>, Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Jonathan Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, Jean-Philippe Brucker <jean-philippe-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
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On 2020/4/14 21:15, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> 
> Add a check to the bus_iommu_probe() call-path to make sure it ignores
> devices which have already been successfully probed. Then export the
> bus_iommu_probe() function so it can be used by IOMMU drivers.
> 
> Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> ---
>   drivers/iommu/iommu.c | 6 +++++-
>   include/linux/iommu.h | 1 +
>   2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 834a45da0ed0..a2ff95424044 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1615,6 +1615,10 @@ static int probe_iommu_group(struct device *dev, void *data)
>   	if (!dev_iommu_get(dev))
>   		return -ENOMEM;
>   
> +	/* Device is probed already if in a group */
> +	if (iommu_group_get(dev) != NULL)

Same as
	if (iommu_group_get(dev))
?

By the way, do we need to put the group if device has already been
probed?

Best regards,
baolu