linux-kernel - [PATCH v6 4/5] vfio/iommu_type1: Clean up update_dirty_scope in detach

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Date:   Mon, 15 Aug 2022 11:14:36 -0700
From:   Nicolin Chen <nicolinc@...dia.com>
To:     <joro@...tes.org>, <will@...nel.org>, <robin.murphy@....com>,
        <alex.williamson@...hat.com>
CC:     <suravee.suthikulpanit@....com>, <marcan@...can.st>,
        <sven@...npeter.dev>, <alyssa@...enzweig.io>,
        <robdclark@...il.com>, <dwmw2@...radead.org>,
        <baolu.lu@...ux.intel.com>, <mjrosato@...ux.ibm.com>,
        <gerald.schaefer@...ux.ibm.com>, <orsonzhai@...il.com>,
        <baolin.wang@...ux.alibaba.com>, <zhang.lyra@...il.com>,
        <thierry.reding@...il.com>, <vdumpa@...dia.com>,
        <jonathanh@...dia.com>, <jean-philippe@...aro.org>,
        <cohuck@...hat.com>, <jgg@...dia.com>, <tglx@...utronix.de>,
        <shameerali.kolothum.thodi@...wei.com>,
        <thunder.leizhen@...wei.com>, <christophe.jaillet@...adoo.fr>,
        <yangyingliang@...wei.com>, <jon@...id-run.com>,
        <iommu@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
        <asahi@...ts.linux.dev>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        <linux-tegra@...r.kernel.org>,
        <virtualization@...ts.linux-foundation.org>, <kvm@...r.kernel.org>,
        <kevin.tian@...el.com>
Subject: [PATCH v6 4/5] vfio/iommu_type1: Clean up update_dirty_scope in detach_group()

All devices in emulated_iommu_groups have pinned_page_dirty_scope
set, so the update_dirty_scope in the first list_for_each_entry
is always false. Clean it up, and move the "if update_dirty_scope"
part from the detach_group_done routine to the domain_list part.

Suggested-by: Jason Gunthorpe <jgg@...dia.com>
Reviewed-by: Kevin Tian <kevin.tian@...el.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
 drivers/vfio/vfio_iommu_type1.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 523927d61aac..3b63a5a237c9 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2464,14 +2464,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 	struct vfio_iommu *iommu = iommu_data;
 	struct vfio_domain *domain;
 	struct vfio_iommu_group *group;
-	bool update_dirty_scope = false;
 	LIST_HEAD(iova_copy);
 
 	mutex_lock(&iommu->lock);
 	list_for_each_entry(group, &iommu->emulated_iommu_groups, next) {
 		if (group->iommu_group != iommu_group)
 			continue;
-		update_dirty_scope = !group->pinned_page_dirty_scope;
 		list_del(&group->next);
 		kfree(group);
 
@@ -2480,7 +2478,8 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 			WARN_ON(!list_empty(&iommu->device_list));
 			vfio_iommu_unmap_unpin_all(iommu);
 		}
-		goto detach_group_done;
+		mutex_unlock(&iommu->lock);
+		return;
 	}
 
 	/*
@@ -2496,9 +2495,7 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 			continue;
 
 		iommu_detach_group(domain->domain, group->iommu_group);
-		update_dirty_scope = !group->pinned_page_dirty_scope;
 		list_del(&group->next);
-		kfree(group);
 		/*
 		 * Group ownership provides privilege, if the group list is
 		 * empty, the domain goes away. If it's the last domain with
@@ -2522,6 +2519,16 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 			vfio_iommu_aper_expand(iommu, &iova_copy);
 			vfio_update_pgsize_bitmap(iommu);
 		}
+		/*
+		 * Removal of a group without dirty tracking may allow
+		 * the iommu scope to be promoted.
+		 */
+		if (!group->pinned_page_dirty_scope) {
+			iommu->num_non_pinned_groups--;
+			if (iommu->dirty_page_tracking)
+				vfio_iommu_populate_bitmap_full(iommu);
+		}
+		kfree(group);
 		break;
 	}
 
@@ -2530,16 +2537,6 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 	else
 		vfio_iommu_iova_free(&iova_copy);
 
-detach_group_done:
-	/*
-	 * Removal of a group without dirty tracking may allow the iommu scope
-	 * to be promoted.
-	 */
-	if (update_dirty_scope) {
-		iommu->num_non_pinned_groups--;
-		if (iommu->dirty_page_tracking)
-			vfio_iommu_populate_bitmap_full(iommu);
-	}
 	mutex_unlock(&iommu->lock);
 }
 
-- 
2.17.1