From: Thierry Reding treding@nvidia.com
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@nvidia.com --- 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); }