On 5/20/23 2:42 AM, Jason Gunthorpe wrote:
Move the driver init and destruction code into two logically paired functions. There is a subtle ordering dependency in how the group's domains are freed, the current code does the kobject_put() on the group which will hopefully trigger the free of the domains before the module_put() that protects the domain->ops. Reorganize this to be explicit and documented. The domains are cleaned up by iommu_deinit_device() if it is the last device to be deinit'd from the group. This must be done in a specific order - after ops->release_device() and before the module_put(). Make it very clear and obvious by putting the order directly in one function. Leave WARN_ON's in case the refcounting gets messed up somehow. This also moves the module_put() and dev_iommu_free() under the group->mutex to keep the code simple. Building paired functions like this helps ensure that error cleanup flows in __iommu_probe_device() are correct because they share the same code that handles the normal flow. These details become relavent as following patches add more error unwind into __iommu_probe_device(), and ultimately a following series adds fine-grained locking to __iommu_probe_device(). Reviewed-by: Kevin Tian<kevin.tian@xxxxxxxxx> Signed-off-by: Jason Gunthorpe<jgg@xxxxxxxxxx>
Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> Best regards, baolu
