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iommu/vt-d: Remove unnecessary rcu_read_locks

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We use RCU's for rarely updated lists like iommus, rmrr, atsr units.

I'm not sure why domain_remove_dev_info() in domain_exit() was surrounded
by rcu_read_lock. Lock was present before refactoring in d160aca527,
but it was related to rcu list, not domain_remove_dev_info function.

dmar_remove_one_dev_info() doesn't touch any of those lists, so it doesn't
require a lock. In fact it is called 6 times without it anyway.

Fixes: d160aca5276d ("iommu/vt-d: Unify domain->iommu attach/detachment")

Signed-off-by: Lukasz Odzioba <lukasz.odzioba@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lukasz Odzioba 2019-05-20 15:41:28 +02:00 committed by Joerg Roedel
parent d7af4d987d
commit f780a8dc19
1 changed files with 0 additions and 4 deletions
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4
drivers/iommu/intel-iommu.c
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@ -1911,9 +1911,7 @@ static void domain_exit(struct dmar_domain *domain)
struct page *freelist;
/* Remove associated devices and clear attached or cached domains */
rcu_read_lock();
domain_remove_dev_info(domain);
rcu_read_unlock();
/* destroy iovas */
put_iova_domain(&domain->iovad);
@ -5254,9 +5252,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
old_domain = find_domain(dev);
if (old_domain) {
rcu_read_lock();
dmar_remove_one_dev_info(dev);
rcu_read_unlock();
if (!domain_type_is_vm_or_si(old_domain) &&
list_empty(&old_domain->devices))