iommu/amd: Don't call the inv_ctx_cb when pasid is not set up

On the error path of amd_iommu_bind_pasid() we call
mmu_notifier_unregister() for cleanup. This calls
mn_release() which calls the users inv_ctx_cb function if
one is available. Since the pasid is not set up yet there is
nothing the user can to tear down in this call-back. So
don't call inv_ctx_cb on the error path of
amd_iommu_unbind_pasid() and make life of the users simpler.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Oded Gabbay <Oded.Gabbay@amd.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index f7ca009bda67..a195c78b63c6 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -52,7 +52,8 @@ 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 */
+        bool invalid;                           /* Used during setup and
+                                                   teardown of the pasid */
         spinlock_t lock;                        /* Protect pri_queues and
                                                    mmu_notifer_count */
         wait_queue_head_t wq;                   /* To wait for count == 0 */
@@ -473,13 +474,15 @@ static void mn_release(struct mmu_notifier *mn, struct mm_struct *mm)
 {
         struct pasid_state *pasid_state;
         struct device_state *dev_state;
+        bool run_inv_ctx_cb;
 
         might_sleep();
 
-        pasid_state = mn_to_state(mn);
-        dev_state   = pasid_state->device_state;
+        pasid_state    = mn_to_state(mn);
+        dev_state      = pasid_state->device_state;
+        run_inv_ctx_cb = !pasid_state->invalid;
 
-        if (pasid_state->device_state->inv_ctx_cb)
+        if (run_inv_ctx_cb && pasid_state->device_state->inv_ctx_cb)
                 dev_state->inv_ctx_cb(dev_state->pdev, pasid_state->pasid);
 
         unbind_pasid(pasid_state);
@@ -674,7 +677,8 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
         pasid_state->mm           = mm;
         pasid_state->device_state = dev_state;
         pasid_state->pasid        = pasid;
-        pasid_state->invalid      = false;
+        pasid_state->invalid      = true; /* Mark as valid only if we are
+                                             done with setting up the pasid */
         pasid_state->mn.ops       = &iommu_mn;
 
         if (pasid_state->mm == NULL)
@@ -691,6 +695,9 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
         if (ret)
                 goto out_clear_state;
 
+        /* Now we are ready to handle faults */
+        pasid_state->invalid = false;
+
         /*
          * Drop the reference to the mm_struct here. We rely on the
          * mmu_notifier release call-back to inform us when the mm