linux-kernel - [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush

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Date:   Thu, 19 Mar 2020 21:32:29 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     LKML <linux-kernel@...r.kernel.org>,
        iommu@...ts.linux-foundation.org,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     Raj Ashok <ashok.raj@...el.com>, "Yi Liu" <yi.l.liu@...el.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush

IOTLB flush already included in the PASID tear down process. There
is no need to flush again.

Cc: Lu Baolu <baolu.lu@...ux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
---
 drivers/iommu/intel-svm.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 8f42d717d8d7..1483f1845762 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -268,10 +268,9 @@ static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	 * *has* to handle gracefully without affecting other processes.
 	 */
 	rcu_read_lock();
-	list_for_each_entry_rcu(sdev, &svm->devs, list) {
+	list_for_each_entry_rcu(sdev, &svm->devs, list)
 		intel_pasid_tear_down_entry(svm->iommu, sdev->dev, svm->pasid);
-		intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
-	}
+
 	rcu_read_unlock();
 
 }
@@ -731,7 +730,6 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
 			 * large and has to be physically contiguous. So it's
 			 * hard to be as defensive as we might like. */
 			intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
-			intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
 			kfree_rcu(sdev, rcu);
 
 			if (list_empty(&svm->devs)) {
-- 
2.7.4