[PATCH 8/9] iommu/amd: Don't hold a reference to task_struct

From: Joerg Roedel
Date: Thu Jul 10 2014 - 09:29:40 EST


From: Joerg Roedel <jroedel@xxxxxxx>

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@xxxxxxx>
Tested-by: Oded Gabbay <Oded.Gabbay@xxxxxxx>
---
drivers/iommu/amd_iommu_v2.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 2b848c0..f7ca009 100644
--- 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;
--
1.7.9.5


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