Messages in this thread | | | Date | Thu, 28 Sep 2023 09:33:29 +0800 | Subject | Re: [PATCH] iommu: Sanity check on param list for iommu_get_resv_regions | From | Baolu Lu <> |
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On 9/27/23 10:25 PM, Dawei Li wrote: > In iommu_get_resv_regions(), param list is an argument supplied by caller, > into which callee is supposed to insert resv regions. > > In other words, this 'list' argument is expected to be an empty list, > so make an explicit annotation on it. > > Signed-off-by: Dawei Li <set_pte_at@outlook.com> > --- > drivers/iommu/iommu.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 1ecac2b5c54f..a01c4a7a9d19 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -813,7 +813,7 @@ int iommu_get_group_resv_regions(struct iommu_group *group, > > mutex_lock(&group->mutex); > for_each_group_device(group, device) { > - struct list_head dev_resv_regions; > + LIST_HEAD(dev_resv_regions); > > /* > * Non-API groups still expose reserved_regions in sysfs, > @@ -822,7 +822,6 @@ int iommu_get_group_resv_regions(struct iommu_group *group, > if (!device->dev->iommu) > break; > > - INIT_LIST_HEAD(&dev_resv_regions); > iommu_get_resv_regions(device->dev, &dev_resv_regions); > ret = iommu_insert_device_resv_regions(&dev_resv_regions, head); > iommu_put_resv_regions(device->dev, &dev_resv_regions); > @@ -1061,12 +1060,11 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain, > struct device *dev) > { > struct iommu_resv_region *entry; > - struct list_head mappings; > unsigned long pg_size; > + LIST_HEAD(mappings); > int ret = 0; > > pg_size = domain->pgsize_bitmap ? 1UL << __ffs(domain->pgsize_bitmap) : 0; > - INIT_LIST_HEAD(&mappings); > > if (WARN_ON_ONCE(iommu_is_dma_domain(domain) && !pg_size)) > return -EINVAL; > @@ -2813,6 +2811,9 @@ void iommu_get_resv_regions(struct device *dev, struct list_head *list) > { > const struct iommu_ops *ops = dev_iommu_ops(dev); > > + if (WARN_ON(!list_empty(list))) > + return;
I don't understand why the input list *must* be empty. This interface has already been exported, so please update the comment to explain this new requirement.
> + > if (ops->get_resv_regions) > ops->get_resv_regions(dev, list); > }
Best regards, baolu
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