From: John Garry <john.garry@huawei.com>
To: <joro@8bytes.org>, <robin.murphy@arm.com>
Cc: linuxarm@huawei.com, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, xiyou.wangcong@gmail.com
Subject: [PATCH 2/2] iommu: avoid taking iova_rbtree_lock twice
Date: Fri, 25 Sep 2020 17:51:09 +0800 [thread overview]
Message-ID: <1601027469-221812-3-git-send-email-john.garry@huawei.com> (raw)
In-Reply-To: <1601027469-221812-1-git-send-email-john.garry@huawei.com>
From: Cong Wang <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.
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.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 05e0b462e0d9..921e80f64ae5 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);
--
2.26.2
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next prev parent reply other threads:[~2020-09-25 9:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 9:51 [PATCH 0/2] iommu/iova: Solve longterm IOVA issue John Garry
2020-09-25 9:51 ` [PATCH 1/2] iommu/iova: Flush CPU rcache for when a depot fills John Garry
2020-09-25 11:53 ` Robin Murphy
2020-09-25 14:34 ` John Garry
2020-09-25 16:12 ` John Garry
2020-09-25 9:51 ` John Garry [this message]
2020-09-25 19:26 ` [PATCH 0/2] iommu/iova: Solve longterm IOVA issue Cong Wang
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