Messages in this thread Patch in this message | | | From | Lukasz Odzioba <> | Subject | [PATCH 1/1] iommu/vt-d: Remove unnecessary rcu_read_locks | Date | Mon, 20 May 2019 15:41:28 +0200 |
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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> --- drivers/iommu/intel-iommu.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a209199..1b7ad80 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -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)) -- 1.8.3.1
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