From: Joerg Roedel Date: Wed, 30 Jul 2014 14:04:37 +0000 (+0200) Subject: iommu/amd: Don't set pasid_state->mm to NULL in unbind_pasid X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=fcaa96060809224c4d2092e1e0d6efcf0d342bb4;p=linux-beck.git iommu/amd: Don't set pasid_state->mm to NULL in unbind_pasid With calling te mmu_notifier_register function we hold a reference to the mm_struct that needs to be released in mmu_notifier_unregister. This is true even if the notifier was already unregistered from exit_mmap and the .release call-back has already run. So make sure we call mmu_notifier_unregister unconditionally in amd_iommu_unbind_pasid. Signed-off-by: Joerg Roedel Tested-by: Oded Gabbay --- diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index a195c78b63c6..2b7de882e91c 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -320,13 +320,6 @@ static void unbind_pasid(struct pasid_state *pasid_state) /* Make sure no more pending faults are in the queue */ flush_workqueue(iommu_wq); - - /* - * No more faults are in the work queue and no new faults will be queued - * from here on. We can safely set pasid_state->mm to NULL now as the - * mm_struct might go away after we return. - */ - pasid_state->mm = NULL; } static void free_pasid_states_level1(struct pasid_state **tbl) @@ -756,17 +749,10 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid) clear_pasid_state(dev_state, pasid_state->pasid); /* - * Check if pasid_state->mm is still valid. If mn_release has already - * run it will be NULL and we can't (and don't need to) call - * mmu_notifier_unregister() on it anymore. + * Call mmu_notifier_unregister to drop our reference + * to pasid_state->mm */ - if (pasid_state->mm) { - /* - * This will call the mn_release function and unbind - * the PASID. - */ - mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm); - } + mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm); put_pasid_state_wait(pasid_state); /* Reference taken in amd_iommu_pasid_bind */