Commit 33793748 authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

iommu: Move lock from iommu_change_dev_def_domain() to its caller 



The intention is to make it possible to put group ownership check and
default domain change in a same critical region protected by the group's
mutex lock. No intentional functional change.

Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230322064956.263419-5-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent dba9ca9d

drivers/iommu/iommu.c

+14 −15
Original line number Diff line number Diff line
@@ -2889,7 +2889,7 @@ static int iommu_change_dev_def_domain(struct iommu_group *group, 
	int ret, dev_def_dom;

	struct device *dev;



	mutex_lock(&group->mutex);

	lockdep_assert_held(&group->mutex);



	if (group->default_domain != group->domain) {

		dev_err_ratelimited(prev_dev, "Group not assigned to default domain\n");
@@ -2978,28 +2978,15 @@ static int iommu_change_dev_def_domain(struct iommu_group *group, 
		goto free_new_domain;



	group->domain = group->default_domain;



	/*

	 * Release the mutex here because ops->probe_finalize() call-back of

	 * some vendor IOMMU drivers calls arm_iommu_attach_device() which

	 * in-turn might call back into IOMMU core code, where it tries to take

	 * group->mutex, resulting in a deadlock.

	 */

	mutex_unlock(&group->mutex);



	/* Make sure dma_ops is appropriatley set */

	iommu_group_do_probe_finalize(dev, group->default_domain);

	iommu_domain_free(prev_dom);



	return 0;



free_new_domain:

	iommu_domain_free(group->default_domain);

	group->default_domain = prev_dom;

	group->domain = prev_dom;



out:

	mutex_unlock(&group->mutex);



	return ret;

}
@@ -3089,7 +3076,19 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, 
		goto out;

	}



	mutex_lock(&group->mutex);

	ret = iommu_change_dev_def_domain(group, dev, req_type);

	/*

	 * Release the mutex here because ops->probe_finalize() call-back of

	 * some vendor IOMMU drivers calls arm_iommu_attach_device() which

	 * in-turn might call back into IOMMU core code, where it tries to take

	 * group->mutex, resulting in a deadlock.

	 */

	mutex_unlock(&group->mutex);



	/* Make sure dma_ops is appropriatley set */

	if (!ret)

		iommu_group_do_probe_finalize(dev, group->default_domain);

	ret = ret ?: count;



out: