From: Cong Wang <xiyou.wangcong@gmail.com>
To: iommu@lists.linux-foundation.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] iommu: avoid taking iova_rbtree_lock twice
Date: Wed, 20 Nov 2019 16:13:48 -0800 [thread overview]
Message-ID: <20191121001348.27230-4-xiyou.wangcong@gmail.com> (raw)
In-Reply-To: <20191121001348.27230-1-xiyou.wangcong@gmail.com>
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 the critical section by calling the unlock
versions instead.
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
drivers/iommu/iova.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b82c6f1cbfc2..ba6bd33f2b16 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -390,10 +390,14 @@ 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);
--
2.21.0
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prev parent reply other threads:[~2019-11-21 0:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-21 0:13 [PATCH 0/3] iommu: reduce spinlock contention on fast path Cong Wang
2019-11-21 0:13 ` [PATCH 1/3] iommu: match the original algorithm Cong Wang
2019-11-27 18:00 ` John Garry
2019-11-27 18:38 ` Qian Cai
2019-11-28 19:30 ` Cong Wang
2019-11-21 0:13 ` [PATCH 2/3] iommu: optimize iova_magazine_free_pfns() Cong Wang
2019-11-21 0:13 ` Cong Wang [this message]
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