On 15/04/2021 04:52, chenxiang wrote:
From: Xiang Chen <[email protected]>
It is not necessary to put free_iova_mem() inside of spinlock/unlock
iova_rbtree_lock which only leads to more completion for the spinlock.
It has a small promote on the performance after the change. And also
rename private_free_iova() as remove_iova() because the function will not
free iova after that change.
Signed-off-by: Xiang Chen <[email protected]>
---
drivers/iommu/iova.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b7ecd5b..c10af23 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -412,12 +412,11 @@ private_find_iova(struct iova_domain *iovad, unsigned
long pfn)
return NULL;
}
-static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
+static void remove_iova(struct iova_domain *iovad, struct iova *iova)
{
assert_spin_locked(&iovad->iova_rbtree_lock);
__cached_rbnode_delete_update(iovad, iova);
rb_erase(&iova->node, &iovad->rbroot);
- free_iova_mem(iova);
}
/**
@@ -452,8 +451,9 @@ __free_iova(struct iova_domain *iovad, struct iova *iova)
unsigned long flags;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
- private_free_iova(iovad, iova);
+ remove_iova(iovad, iova);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+ free_iova_mem(iova);
}
EXPORT_SYMBOL_GPL(__free_iova);
@@ -473,9 +473,9 @@ free_iova(struct iova_domain *iovad, unsigned long pfn)
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
iova = private_find_iova(iovad, pfn);
if (iova)
- private_free_iova(iovad, iova);
+ remove_iova(iovad, iova);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-
+ free_iova_mem(iova);
you need to make this:
if (iova)
free_iova_mem(iova);
as free_iova_mem(iova) dereferences iova:
if (iova->pfn_lo != IOVA_ANCHOR)
kmem_cache_free(iova_cache, iova)
So if iova were NULL, we crash.
Or you can make free_iova_mem() NULL safe.
}
EXPORT_SYMBOL_GPL(free_iova);
@@ -825,7 +825,8 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
if (WARN_ON(!iova))
continue;
- private_free_iova(iovad, iova);
+ remove_iova(iovad, iova);
+ free_iova_mem(iova);
}
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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