iommu/amd: Don't hold a reference to task_struct

Since we are only caring about the lifetime of the mm_struct
and not the task we can't safely keep a reference to it. The
reference is also not needed anymore, so remove that code
entirely.

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

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 2b848c0..f7ca009 100644 (file)
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -47,7 +47,6 @@ struct pasid_state {
        atomic_t count;                         /* Reference count */
        unsigned mmu_notifier_count;            /* Counting nested mmu_notifier
                                                   calls */
-       struct task_struct *task;               /* Task bound to this PASID */
        struct mm_struct *mm;                   /* mm_struct for the faults */
        struct mmu_notifier mn;                 /* mmu_notifier handle */
        struct pri_queue pri[PRI_QUEUE_SIZE];   /* PRI tag states */
@@ -531,7 +530,7 @@ static void do_fault(struct work_struct *work)
        write = !!(fault->flags & PPR_FAULT_WRITE);
 
        down_read(&fault->state->mm->mmap_sem);
-       npages = get_user_pages(fault->state->task, fault->state->mm,
+       npages = get_user_pages(NULL, fault->state->mm,
                                fault->address, 1, write, 0, &page, NULL);
        up_read(&fault->state->mm->mmap_sem);
 
@@ -672,7 +671,6 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
        spin_lock_init(&pasid_state->lock);
 
        mm                        = get_task_mm(task);
-       pasid_state->task         = task;
        pasid_state->mm           = mm;
        pasid_state->device_state = dev_state;
        pasid_state->pasid        = pasid;