From 244b2c5ca8b14627e4a17755e5922221e121c771 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:15:07 +0000
Subject: [PATCH] change system file
---
kernel/drivers/iommu/iommu.c | 28 ++++++++++++++++++++++------
1 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/kernel/drivers/iommu/iommu.c b/kernel/drivers/iommu/iommu.c
index 793c528..64d7a37 100644
--- a/kernel/drivers/iommu/iommu.c
+++ b/kernel/drivers/iommu/iommu.c
@@ -201,13 +201,23 @@
const struct iommu_ops *ops = dev->bus->iommu_ops;
struct iommu_device *iommu_dev;
struct iommu_group *group;
+ static DEFINE_MUTEX(iommu_probe_device_lock);
int ret;
if (!ops)
return -ENODEV;
-
- if (!dev_iommu_get(dev))
- return -ENOMEM;
+ /*
+ * Serialise to avoid races between IOMMU drivers registering in
+ * parallel and/or the "replay" calls from ACPI/OF code via client
+ * driver probe. Once the latter have been cleaned up we should
+ * probably be able to use device_lock() here to minimise the scope,
+ * but for now enforcing a simple global ordering is fine.
+ */
+ mutex_lock(&iommu_probe_device_lock);
+ if (!dev_iommu_get(dev)) {
+ ret = -ENOMEM;
+ goto err_unlock;
+ }
if (!try_module_get(ops->owner)) {
ret = -EINVAL;
@@ -227,11 +237,14 @@
ret = PTR_ERR(group);
goto out_release;
}
- iommu_group_put(group);
+ mutex_lock(&group->mutex);
if (group_list && !group->default_domain && list_empty(&group->entry))
list_add_tail(&group->entry, group_list);
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+ mutex_unlock(&iommu_probe_device_lock);
iommu_device_link(iommu_dev, dev);
return 0;
@@ -244,6 +257,9 @@
err_free:
dev_iommu_free(dev);
+
+err_unlock:
+ mutex_unlock(&iommu_probe_device_lock);
return ret;
}
@@ -1766,10 +1782,10 @@
return ret;
list_for_each_entry_safe(group, next, &group_list, entry) {
+ mutex_lock(&group->mutex);
+
/* Remove item from the list */
list_del_init(&group->entry);
-
- mutex_lock(&group->mutex);
/* Try to allocate default domain */
probe_alloc_default_domain(bus, group);
--
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