Commit 3a651b3a authored Nov 17, 2020 by Cong Wang Committed by Will Deacon Dec 01, 2020

iommu: avoid taking iova_rbtree_lock twice



Both find_iova() and __free_iova() take iova_rbtree_lock,
there is no reason to take and release it twice inside
free_iova().

Fold them into one critical section by calling the unlock
versions instead.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1605608734-84416-5-git-send-email-john.garry@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>

parent 6fa3525b

drivers/iommu/iova.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -402,10 +402,14 @@ EXPORT_SYMBOL_GPL(__free_iova);
		void
		free_iova(struct iova_domain *iovad, unsigned long pfn)
		{
		struct iova *iova = find_iova(iovad, pfn);
		unsigned long flags;
		struct iova *iova;

		spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
		iova = private_find_iova(iovad, pfn);
		if (iova)
		__free_iova(iovad, iova);
		private_free_iova(iovad, iova);
		spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);

		}
		EXPORT_SYMBOL_GPL(free_iova);

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