To support driver-allocated vIOMMU objects, it's required for IOMMU driver
to call the provided iommufd_viommu_alloc helper to embed the core struct.
However, there is no guarantee that every driver will call it and allocate
objects properly.
Make the iommufd_object_finalize/abort functions more robust to verify if
the xarray slot indexed by the input obj->id is having an XA_ZERO_ENTRY,
which is the reserved value stored by xa_alloc via iommufd_object_alloc.
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
drivers/iommu/iommufd/main.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 3c32b440471b..30e6c2af3b45 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -41,20 +41,26 @@ static struct miscdevice vfio_misc_dev;
void iommufd_object_finalize(struct iommufd_ctx *ictx,
struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_store(&ictx->objects, obj->id, obj, GFP_KERNEL);
- /* obj->id was returned from xa_alloc() so the xa_store() cannot fail */
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, obj);
+ xa_unlock(&ictx->objects);
+ /* obj->id was returned from xa_alloc() so the xas_store() cannot fail */
+ WARN_ON(old != XA_ZERO_ENTRY);
}
/* Undo _iommufd_object_alloc() if iommufd_object_finalize() was not called */
void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj)
{
+ XA_STATE(xas, &ictx->objects, obj->id);
void *old;
- old = xa_erase(&ictx->objects, obj->id);
- WARN_ON(old);
+ xa_lock(&ictx->objects);
+ old = xas_store(&xas, NULL);
+ xa_unlock(&ictx->objects);
+ WARN_ON(old != XA_ZERO_ENTRY);
kfree(obj);
}
--
2.43.0
