On 14.05.2018 13:13, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> The IOVA API uses a memory cache to allocate IOVA nodes from. To make
> sure that this cache is available, obtain a reference to it and release
> the reference when the cache is no longer needed.
>
> On 64-bit ARM this is hidden by the fact that the DMA mapping API gets
> that reference and never releases it. On 32-bit ARM, this is papered
> over by the Tegra DRM driver (the sole user of the host1x API requiring
> the cache) acquiring a reference to the IOVA cache for its own purposes.
> However, there may be additional users of this API in the future, so fix
> this upfront to avoid surprises.
>
> Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support")
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/gpu/host1x/dev.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
> index 03db71173f5d..f1d5f76e9c33 100644
> --- a/drivers/gpu/host1x/dev.c
> +++ b/drivers/gpu/host1x/dev.c
> @@ -223,10 +223,14 @@ static int host1x_probe(struct platform_device *pdev)
> struct iommu_domain_geometry *geometry;
> unsigned long order;
>
> + err = iova_cache_get();
> + if (err < 0)
> + goto put_group;
> +
> host->domain = iommu_domain_alloc(&platform_bus_type);
> if (!host->domain) {
> err = -ENOMEM;
> - goto put_group;
> + goto put_cache;
> }
>
> err = iommu_attach_group(host->domain, host->group);
> @@ -234,6 +238,7 @@ static int host1x_probe(struct platform_device *pdev)
> if (err == -ENODEV) {
> iommu_domain_free(host->domain);
> host->domain = NULL;
> + iova_cache_put();
> iommu_group_put(host->group);
> host->group = NULL;
> goto skip_iommu;
> @@ -308,6 +313,9 @@ static int host1x_probe(struct platform_device *pdev)
> fail_free_domain:
> if (host->domain)
> iommu_domain_free(host->domain);
> +put_cache:
> + if (host->group)
> + iova_cache_put();
> put_group:
> iommu_group_put(host->group);
>
> @@ -328,6 +336,7 @@ static int host1x_remove(struct platform_device *pdev)
> put_iova_domain(&host->iova);
> iommu_detach_group(host->domain, host->group);
> iommu_domain_free(host->domain);
> + iova_cache_put();
> iommu_group_put(host->group);
> }
>
>
Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>
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