From 33793748de8fde338c11277d3d16dadc79ba65bf Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Wed, 22 Mar 2023 14:49:54 +0800 Subject: 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: Lu Baolu Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20230322064956.263419-5-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 419d5655ce61..32c51e6a3491 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -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: -- cgit v1.2.3