From: Joerg Roedel <[email protected]> This is used to signal the ppr_notifer function that no more faults should be processes on this pasid_state. This way we can keep the pasid_state safely in the state-table so that it can be freed in the amd_iommu_unbind_pasid() function.
This allows us to not hold a reference to the mm_struct during the whole pasid-binding-time. Signed-off-by: Joerg Roedel <[email protected]> Tested-by: Oded Gabbay <[email protected]> --- drivers/iommu/amd_iommu_v2.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index 6ba707b..69a46f1 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -53,6 +53,7 @@ struct pasid_state { struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */ struct device_state *device_state; /* Link to our device_state */ int pasid; /* PASID index */ + bool invalid; /* Used during teardown */ spinlock_t lock; /* Protect pri_queues and mmu_notifer_count */ wait_queue_head_t wq; /* To wait for count == 0 */ @@ -306,8 +307,17 @@ static void unbind_pasid(struct pasid_state *pasid_state) domain = pasid_state->device_state->domain; + /* + * Mark pasid_state as invalid, no more faults will we added to the + * work queue after this is visible everywhere. + */ + pasid_state->invalid = true; + + /* Make sure this is visible */ + smp_wmb(); + + /* After this the device/pasid can't access the mm anymore */ amd_iommu_domain_clear_gcr3(domain, pasid_state->pasid); - clear_pasid_state(pasid_state->device_state, pasid_state->pasid); /* Make sure no more pending faults are in the queue */ flush_workqueue(iommu_wq); @@ -573,7 +583,7 @@ static int ppr_notifier(struct notifier_block *nb, unsigned long e, void *data) goto out; pasid_state = get_pasid_state(dev_state, iommu_fault->pasid); - if (pasid_state == NULL) { + if (pasid_state == NULL || pasid_state->invalid) { /* We know the device but not the PASID -> send INVALID */ amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid, PPR_INVALID, tag); @@ -657,6 +667,7 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid, pasid_state->mm = get_task_mm(task); pasid_state->device_state = dev_state; pasid_state->pasid = pasid; + pasid_state->invalid = false; pasid_state->mn.ops = &iommu_mn; if (pasid_state->mm == NULL) @@ -720,6 +731,9 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid) */ put_pasid_state(pasid_state); + /* Clear the pasid state so that the pasid can be re-used */ + clear_pasid_state(dev_state, pasid_state->pasid); + /* This will call the mn_release function and unbind the PASID */ mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
