linux-kernel - [PATCH v3 2/6] iommu: Split iommu_group_remove

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Date:   Mon,  6 Mar 2023 10:58:00 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     iommu@...ts.linux.dev
Cc:     Joerg Roedel <joro@...tes.org>, Jason Gunthorpe <jgg@...dia.com>,
        Christoph Hellwig <hch@...radead.org>,
        Kevin Tian <kevin.tian@...el.com>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v3 2/6] iommu: Split iommu_group_remove_device() into helpers

So that code could be re-used by iommu_release_device() in the subsequent
change. No intention for functionality change.

Signed-off-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/iommu.c | 64 +++++++++++++++++++++++++++++--------------
 1 file changed, 44 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 80211bf08c0d..bd9b293e07a8 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -465,6 +465,46 @@ int iommu_probe_device(struct device *dev)
 
 }
 
+/*
+ * Remove a device from a group's device list and return the group device
+ * if successful.
+ */
+static struct group_device *
+__iommu_group_remove_device(struct iommu_group *group, struct device *dev)
+{
+	struct group_device *device;
+
+	lockdep_assert_held(&group->mutex);
+	list_for_each_entry(device, &group->devices, list) {
+		if (device->dev == dev) {
+			list_del(&device->list);
+			return device;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Release a device from its group and decrements the iommu group reference
+ * count.
+ */
+static void __iommu_group_release_device(struct iommu_group *group,
+					 struct group_device *grp_dev)
+{
+	struct device *dev = grp_dev->dev;
+
+	sysfs_remove_link(group->devices_kobj, grp_dev->name);
+	sysfs_remove_link(&dev->kobj, "iommu_group");
+
+	trace_remove_device_from_group(group->id, dev);
+
+	kfree(grp_dev->name);
+	kfree(grp_dev);
+	dev->iommu_group = NULL;
+	kobject_put(group->devices_kobj);
+}
+
 void iommu_release_device(struct device *dev)
 {
 	const struct iommu_ops *ops;
@@ -1080,7 +1120,7 @@ EXPORT_SYMBOL_GPL(iommu_group_add_device);
 void iommu_group_remove_device(struct device *dev)
 {
 	struct iommu_group *group = dev->iommu_group;
-	struct group_device *tmp_device, *device = NULL;
+	struct group_device *device;
 
 	if (!group)
 		return;
@@ -1088,27 +1128,11 @@ void iommu_group_remove_device(struct device *dev)
 	dev_info(dev, "Removing from iommu group %d\n", group->id);
 
 	mutex_lock(&group->mutex);
-	list_for_each_entry(tmp_device, &group->devices, list) {
-		if (tmp_device->dev == dev) {
-			device = tmp_device;
-			list_del(&device->list);
-			break;
-		}
-	}
+	device = __iommu_group_remove_device(group, dev);
 	mutex_unlock(&group->mutex);
 
-	if (!device)
-		return;
-
-	sysfs_remove_link(group->devices_kobj, device->name);
-	sysfs_remove_link(&dev->kobj, "iommu_group");
-
-	trace_remove_device_from_group(group->id, dev);
-
-	kfree(device->name);
-	kfree(device);
-	dev->iommu_group = NULL;
-	kobject_put(group->devices_kobj);
+	if (device)
+		__iommu_group_release_device(group, device);
 }
 EXPORT_SYMBOL_GPL(iommu_group_remove_device);
 
-- 
2.34.1