From: Cong Wang <xiyou.wangcong@gmail.com>
To: iommu@lists.linux-foundation.org
Cc: robin.murphy@arm.com, linux-kernel@vger.kernel.org,
joro@8bytes.org, Cong Wang <xiyou.wangcong@gmail.com>,
John Garry <john.garry@huawei.com>
Subject: [Patch v3 3/3] iommu: avoid taking iova_rbtree_lock twice
Date: Tue, 17 Dec 2019 20:39:51 -0800 [thread overview]
Message-ID: <20191218043951.10534-4-xiyou.wangcong@gmail.com> (raw)
In-Reply-To: <20191218043951.10534-1-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 one critical section by calling the unlock
versions instead.
Cc: Joerg Roedel <joro@8bytes.org>
Cc: John Garry <john.garry@huawei.com>
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 184d4c0e20b5..f46f8f794678 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
next prev parent reply other threads:[~2019-12-18 4:40 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 4:39 [Patch v3 0/3] iommu: reduce spinlock contention on fast path Cong Wang
2019-12-18 4:39 ` [Patch v3 1/3] iommu: avoid unnecessary magazine allocations Cong Wang
2020-01-21 11:11 ` Robin Murphy
2020-01-21 17:21 ` Cong Wang
2020-01-22 17:07 ` Robin Murphy
2020-01-22 17:54 ` Cong Wang
2019-12-18 4:39 ` [Patch v3 2/3] iommu: optimize iova_magazine_free_pfns() Cong Wang
2020-01-21 9:52 ` Robin Murphy
2020-01-21 17:29 ` Cong Wang
2020-01-22 17:34 ` Robin Murphy
2020-01-22 17:45 ` Cong Wang
2019-12-18 4:39 ` Cong Wang [this message]
2019-12-19 9:51 ` [Patch v3 3/3] iommu: avoid taking iova_rbtree_lock twice John Garry
2020-01-21 9:56 ` Robin Murphy
2020-03-03 11:33 ` John Garry
2020-01-20 23:10 ` [Patch v3 0/3] iommu: reduce spinlock contention on fast path Cong Wang
-- strict thread matches above, loose matches on Subject: below --
2019-12-06 21:38 Cong Wang
2019-12-06 21:38 ` [Patch v3 3/3] iommu: avoid taking iova_rbtree_lock twice Cong Wang
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