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Commit fcaa9606 authored by Joerg Roedel's avatar Joerg Roedel
Browse files

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: default avatarJoerg Roedel <jroedel@suse.de>
Tested-by: default avatarOded Gabbay <oded.gabbay@amd.com>
parent d9e1611e

drivers/iommu/amd_iommu_v2.c

+3 −17
Original line number Diff line number Diff line
@@ -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.

	 */

	if (pasid_state->mm) {

		/*

		 * This will call the mn_release function and unbind

		 * the PASID.

	 * Call mmu_notifier_unregister to drop our reference

	 * to 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 */