iommu/vt-d: Remove unnecessary rcu_read_locks (f780a8dc) · Commits · 戴 / test

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 , 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: ("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>

drivers/iommu/intel-iommu.c

+0 −4

Original line number	Original line	Diff line number	Diff line
	@@ -1911,9 +1911,7 @@ static void domain_exit(struct dmar_domain *domain)
	struct page *freelist;		struct page *freelist;

	/* Remove associated devices and clear attached or cached domains */		/* Remove associated devices and clear attached or cached domains */
	rcu_read_lock();
	domain_remove_dev_info(domain);		domain_remove_dev_info(domain);
	rcu_read_unlock();

	/* destroy iovas */		/* destroy iovas */
	put_iova_domain(&domain->iovad);		put_iova_domain(&domain->iovad);
	@@ -5254,9 +5252,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,

	old_domain = find_domain(dev);		old_domain = find_domain(dev);
	if (old_domain) {		if (old_domain) {
	rcu_read_lock();
	dmar_remove_one_dev_info(dev);		dmar_remove_one_dev_info(dev);
	rcu_read_unlock();

	if (!domain_type_is_vm_or_si(old_domain) &&		if (!domain_type_is_vm_or_si(old_domain) &&
	list_empty(&old_domain->devices))		list_empty(&old_domain->devices))

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