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iommu/amd: Don't set pasid_state->mm to NULL in unbind_pasid

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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 <jroedel@suse.de>
Tested-by: Oded Gabbay <oded.gabbay@amd.com>
This commit is contained in:
Joerg Roedel 2014-07-30 16:04:37 +02:00
parent d9e1611e73
commit fcaa960608
1 changed files with 3 additions and 17 deletions
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20
drivers/iommu/amd_iommu_v2.c
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@ -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 */