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[PATCH v2 0/7] iommu/iova: improve the allocation performance of dma64

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  [PATCH v2 0/7] iommu/iova: improve the allocation performance of dma64 Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 4/7] iommu/iova: adjust __cached_rbnode_insert_update Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 3/7] iommu/iova: insert start_pfn boundary of dma32 Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 7/7] iommu/iova: fix iovad->dma_32bit_pfn as the last pfn of dma32 Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 5/7] iommu/iova: to optimize the allocation performance of dma64 Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 2/7] iommu/iova: cut down judgement times Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200
    [PATCH v2 1/7] iommu/iova: fix incorrect variable types Zhen Lei <thunder.leizhen@huawei.com> - 2017-03-31 05:30 +0200

#1613593 — [PATCH v2 0/7] iommu/iova: improve the allocation performance of dma64

v1 -> v2:
Because the problem of my email-server, all patches sent to Joerg Roedel <joro@8bytes.org> failed.
So I repost all these patches again, there is no changes.

v1:
64 bits devices is very common now. But currently we only defined a cached32_node
to optimize the allocation performance of dma32, and I saw some dma64 drivers chose
to allocate iova from dma32 space first, maybe becuase of current dma64 performance
problem or some other reasons.

For example:(in drivers/iommu/amd_iommu.c)
static unsigned long dma_ops_alloc_iova(......
{
	......
	if (dma_mask > DMA_BIT_MASK(32))
		pfn = alloc_iova_fast(&dma_dom->iovad, pages,
				      IOVA_PFN(DMA_BIT_MASK(32)));
	if (!pfn)
		pfn = alloc_iova_fast(&dma_dom->iovad, pages, IOVA_PFN(dma_mask));
		
For the details of why dma64 iova allocation performance is very bad, please refer the
description of patch-5.

In this patch series, I added a cached64_node to manage the dma64 iova space(iova>=4G), it
takes the same effect as cached32_node(iova<4G).

Below it's the performance data before and after my patch series:
(before)$ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35898
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.2 sec  7.88 MBytes  6.48 Mbits/sec
[  5] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35900
[  5]  0.0-10.3 sec  7.88 MBytes  6.43 Mbits/sec
[  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 35902
[  4]  0.0-10.3 sec  7.88 MBytes  6.43 Mbits/sec

(after)$ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36330
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec  1.09 GBytes   933 Mbits/sec
[  5] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36332
[  5]  0.0-10.0 sec  1.10 GBytes   939 Mbits/sec
[  4] local 192.168.1.106 port 5001 connected with 192.168.1.198 port 36334
[  4]  0.0-10.0 sec  1.10 GBytes   938 Mbits/sec


Zhen Lei (7):
  iommu/iova: fix incorrect variable types
  iommu/iova: cut down judgement times
  iommu/iova: insert start_pfn boundary of dma32
  iommu/iova: adjust __cached_rbnode_insert_update
  iommu/iova: to optimize the allocation performance of dma64
  iommu/iova: move the caculation of pad mask out of loop
  iommu/iova: fix iovad->dma_32bit_pfn as the last pfn of dma32

 drivers/iommu/amd_iommu.c        |   7 +-
 drivers/iommu/dma-iommu.c        |  22 ++----
 drivers/iommu/intel-iommu.c      |  11 +--
 drivers/iommu/iova.c             | 143 +++++++++++++++++++++------------------
 drivers/misc/mic/scif/scif_rma.c |   3 +-
 include/linux/iova.h             |   7 +-
 6 files changed, 94 insertions(+), 99 deletions(-)

-- 
2.5.0

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#1613594 — [PATCH v2 4/7] iommu/iova: adjust __cached_rbnode_insert_update

For case 2 and 3, adjust cached32_node to the new place, case 1 keep no
change.

For example:
case1: (the right part was allocated)
	|------------------------------|
	|<-----free---->|<--new_iova-->|
	|
	|
   cached32_node

case2: (all was allocated)
	|------------------------------|
	|<---------new_iova----------->|
	|
	|
   cached32_node

case3:
	|-----------------------|......|---------|
        |..free..|<--new_iova-->|<not enough iova space>
        |                              |
        |                              |
   cached32_node(new)             cached32_node(old)

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/iova.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b5a148e..87a9332 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -91,12 +91,16 @@ __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
 }
 
 static void
-__cached_rbnode_insert_update(struct iova_domain *iovad,
-	unsigned long limit_pfn, struct iova *new)
+__cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
 {
-	if (limit_pfn != iovad->dma_32bit_pfn)
+	struct iova *cached_iova;
+
+	if (new->pfn_hi > iovad->dma_32bit_pfn)
 		return;
-	iovad->cached32_node = &new->node;
+
+	cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
+	if (new->pfn_lo <= cached_iova->pfn_lo)
+		iovad->cached32_node = rb_prev(&new->node);
 }
 
 static void
@@ -131,12 +135,10 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 {
 	struct rb_node *prev, *curr;
 	unsigned long flags;
-	unsigned long saved_pfn;
 	unsigned long pad_size = 0;
 
 	/* Walk the tree backwards */
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
-	saved_pfn = limit_pfn;
 	curr = __get_cached_rbnode(iovad, &limit_pfn);
 	prev = curr;
 	while (curr) {
@@ -197,11 +199,10 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 		rb_link_node(&new->node, parent, entry);
 		rb_insert_color(&new->node, &iovad->rbroot);
 	}
-	__cached_rbnode_insert_update(iovad, saved_pfn, new);
+	__cached_rbnode_insert_update(iovad, new);
 
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 
-
 	return 0;
 }
 
-- 
2.5.0

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#1613596 — [PATCH v2 3/7] iommu/iova: insert start_pfn boundary of dma32

Reserve the first granule size memory(start at start_pfn) as boundary
iova, to make sure that iovad->cached32_node can not be NULL in future.
Meanwhile, changed the assignment of iovad->cached32_node from rb_next to
rb_prev of &free->node in function __cached_rbnode_delete_update.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/iova.c | 63 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 37 insertions(+), 26 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 1c49969..b5a148e 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -32,6 +32,17 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
 static void init_iova_rcaches(struct iova_domain *iovad);
 static void free_iova_rcaches(struct iova_domain *iovad);
 
+static void
+insert_iova_boundary(struct iova_domain *iovad)
+{
+	struct iova *iova;
+	unsigned long start_pfn_32bit = iovad->start_pfn;
+
+	iova = reserve_iova(iovad, start_pfn_32bit, start_pfn_32bit);
+	BUG_ON(!iova);
+	iovad->cached32_node = &iova->node;
+}
+
 void
 init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	unsigned long start_pfn, unsigned long pfn_32bit)
@@ -45,27 +56,38 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 
 	spin_lock_init(&iovad->iova_rbtree_lock);
 	iovad->rbroot = RB_ROOT;
-	iovad->cached32_node = NULL;
 	iovad->granule = granule;
 	iovad->start_pfn = start_pfn;
 	iovad->dma_32bit_pfn = pfn_32bit;
 	init_iova_rcaches(iovad);
+
+	/*
+	 * Insert boundary nodes for dma32. So cached32_node can not be NULL in
+	 * future.
+	 */
+	insert_iova_boundary(iovad);
 }
 EXPORT_SYMBOL_GPL(init_iova_domain);
 
 static struct rb_node *
 __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
 {
-	if ((*limit_pfn > iovad->dma_32bit_pfn) ||
-		(iovad->cached32_node == NULL))
+	struct rb_node *cached_node;
+	struct rb_node *next_node;
+
+	if (*limit_pfn > iovad->dma_32bit_pfn)
 		return rb_last(&iovad->rbroot);
-	else {
-		struct rb_node *prev_node = rb_prev(iovad->cached32_node);
-		struct iova *curr_iova =
-			rb_entry(iovad->cached32_node, struct iova, node);
-		*limit_pfn = curr_iova->pfn_lo - 1;
-		return prev_node;
+	else
+		cached_node = iovad->cached32_node;
+
+	next_node = rb_next(cached_node);
+	if (next_node) {
+		struct iova *next_iova = rb_entry(next_node, struct iova, node);
+
+		*limit_pfn = min(*limit_pfn, next_iova->pfn_lo - 1);
 	}
+
+	return cached_node;
 }
 
 static void
@@ -83,20 +105,13 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
 	struct iova *cached_iova;
 	struct rb_node *curr;
 
-	if (!iovad->cached32_node)
-		return;
 	curr = iovad->cached32_node;
 	cached_iova = rb_entry(curr, struct iova, node);
 
 	if (free->pfn_lo >= cached_iova->pfn_lo) {
-		struct rb_node *node = rb_next(&free->node);
-		struct iova *iova = rb_entry(node, struct iova, node);
-
 		/* only cache if it's below 32bit pfn */
-		if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
-			iovad->cached32_node = node;
-		else
-			iovad->cached32_node = NULL;
+		if (free->pfn_hi <= iovad->dma_32bit_pfn)
+			iovad->cached32_node = rb_prev(&free->node);
 	}
 }
 
@@ -114,7 +129,7 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 		unsigned long size, unsigned long limit_pfn,
 			struct iova *new, bool size_aligned)
 {
-	struct rb_node *prev, *curr = NULL;
+	struct rb_node *prev, *curr;
 	unsigned long flags;
 	unsigned long saved_pfn;
 	unsigned long pad_size = 0;
@@ -144,13 +159,9 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 		curr = rb_prev(curr);
 	}
 
-	if (!curr) {
-		if (size_aligned)
-			pad_size = iova_get_pad_size(size, limit_pfn);
-		if ((iovad->start_pfn + size + pad_size) > limit_pfn) {
-			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-			return -ENOMEM;
-		}
+	if (unlikely(!curr)) {
+		spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+		return -ENOMEM;
 	}
 
 	/* pfn_lo will point to size aligned address if size_aligned is set */
-- 
2.5.0

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#1613597 — [PATCH v2 7/7] iommu/iova: fix iovad->dma_32bit_pfn as the last pfn of dma32

To make sure iovad->cached32_node and iovad->cached64_node can exactly
control dma32 and dma64 area. It also help us to remove the parameter
pfn_32bit of init_iova_domain.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/amd_iommu.c        |  7 ++-----
 drivers/iommu/dma-iommu.c        | 22 +++++-----------------
 drivers/iommu/intel-iommu.c      | 11 +++--------
 drivers/iommu/iova.c             |  4 ++--
 drivers/misc/mic/scif/scif_rma.c |  3 +--
 include/linux/iova.h             |  2 +-
 6 files changed, 14 insertions(+), 35 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 98940d1..78c8b93 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -61,7 +61,6 @@
 /* IO virtual address start page frame number */
 #define IOVA_START_PFN		(1)
 #define IOVA_PFN(addr)		((addr) >> PAGE_SHIFT)
-#define DMA_32BIT_PFN		IOVA_PFN(DMA_BIT_MASK(32))
 
 /* Reserved IOVA ranges */
 #define MSI_RANGE_START		(0xfee00000)
@@ -1776,8 +1775,7 @@ static struct dma_ops_domain *dma_ops_domain_alloc(void)
 	if (!dma_dom->domain.pt_root)
 		goto free_dma_dom;
 
-	init_iova_domain(&dma_dom->iovad, PAGE_SIZE,
-			 IOVA_START_PFN, DMA_32BIT_PFN);
+	init_iova_domain(&dma_dom->iovad, PAGE_SIZE, IOVA_START_PFN);
 
 	/* Initialize reserved ranges */
 	copy_reserved_iova(&reserved_iova_ranges, &dma_dom->iovad);
@@ -2747,8 +2745,7 @@ static int init_reserved_iova_ranges(void)
 	struct pci_dev *pdev = NULL;
 	struct iova *val;
 
-	init_iova_domain(&reserved_iova_ranges, PAGE_SIZE,
-			 IOVA_START_PFN, DMA_32BIT_PFN);
+	init_iova_domain(&reserved_iova_ranges, PAGE_SIZE, IOVA_START_PFN);
 
 	lockdep_set_class(&reserved_iova_ranges.iova_rbtree_lock,
 			  &reserved_rbtree_key);
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 48d36ce..7064d32 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -223,18 +223,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 		/* ...then finally give it a kicking to make sure it fits */
 		base_pfn = max_t(unsigned long, base_pfn,
 				domain->geometry.aperture_start >> order);
-		end_pfn = min_t(unsigned long, end_pfn,
-				domain->geometry.aperture_end >> order);
 	}
-	/*
-	 * PCI devices may have larger DMA masks, but still prefer allocating
-	 * within a 32-bit mask to avoid DAC addressing. Such limitations don't
-	 * apply to the typical platform device, so for those we may as well
-	 * leave the cache limit at the top of their range to save an rb_last()
-	 * traversal on every allocation.
-	 */
-	if (pci)
-		end_pfn &= DMA_BIT_MASK(32) >> order;
 
 	/* start_pfn is always nonzero for an already-initialised domain */
 	if (iovad->start_pfn) {
@@ -243,16 +232,15 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 			pr_warn("Incompatible range for DMA domain\n");
 			return -EFAULT;
 		}
-		/*
-		 * If we have devices with different DMA masks, move the free
-		 * area cache limit down for the benefit of the smaller one.
-		 */
-		iovad->dma_32bit_pfn = min(end_pfn, iovad->dma_32bit_pfn);
 	} else {
-		init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
+		init_iova_domain(iovad, 1UL << order, base_pfn);
 		if (pci)
 			iova_reserve_pci_windows(to_pci_dev(dev), iovad);
 	}
+
+	if (end_pfn < iovad->dma_32bit_pfn)
+		dev_dbg(dev, "ancient device or dma range missed some bits?");
+
 	return 0;
 }
 EXPORT_SYMBOL(iommu_dma_init_domain);
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 238ad34..de467c1 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -82,8 +82,6 @@
 #define IOVA_START_PFN		(1)
 
 #define IOVA_PFN(addr)		((addr) >> PAGE_SHIFT)
-#define DMA_32BIT_PFN		IOVA_PFN(DMA_BIT_MASK(32))
-#define DMA_64BIT_PFN		IOVA_PFN(DMA_BIT_MASK(64))
 
 /* page table handling */
 #define LEVEL_STRIDE		(9)
@@ -1869,8 +1867,7 @@ static int dmar_init_reserved_ranges(void)
 	struct iova *iova;
 	int i;
 
-	init_iova_domain(&reserved_iova_list, VTD_PAGE_SIZE, IOVA_START_PFN,
-			DMA_32BIT_PFN);
+	init_iova_domain(&reserved_iova_list, VTD_PAGE_SIZE, IOVA_START_PFN);
 
 	lockdep_set_class(&reserved_iova_list.iova_rbtree_lock,
 		&reserved_rbtree_key);
@@ -1928,8 +1925,7 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu,
 	int adjust_width, agaw;
 	unsigned long sagaw;
 
-	init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
-			DMA_32BIT_PFN);
+	init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN);
 	domain_reserve_special_ranges(domain);
 
 	/* calculate AGAW */
@@ -4965,8 +4961,7 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
 {
 	int adjust_width;
 
-	init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
-			DMA_32BIT_PFN);
+	init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN);
 	domain_reserve_special_ranges(domain);
 
 	/* calculate AGAW */
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 68754e4..43fd8e9 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -50,7 +50,7 @@ insert_iova_boundary(struct iova_domain *iovad)
 
 void
 init_iova_domain(struct iova_domain *iovad, unsigned long granule,
-	unsigned long start_pfn, unsigned long pfn_32bit)
+	unsigned long start_pfn)
 {
 	/*
 	 * IOVA granularity will normally be equal to the smallest
@@ -63,7 +63,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	iovad->rbroot = RB_ROOT;
 	iovad->granule = granule;
 	iovad->start_pfn = start_pfn;
-	iovad->dma_32bit_pfn = pfn_32bit;
+	iovad->dma_32bit_pfn = DMA_BIT_MASK(32) >> ilog2(granule);
 	init_iova_rcaches(iovad);
 
 	/*
diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c
index 329727e..c824329 100644
--- a/drivers/misc/mic/scif/scif_rma.c
+++ b/drivers/misc/mic/scif/scif_rma.c
@@ -39,8 +39,7 @@ void scif_rma_ep_init(struct scif_endpt *ep)
 	struct scif_endpt_rma_info *rma = &ep->rma_info;
 
 	mutex_init(&rma->rma_lock);
-	init_iova_domain(&rma->iovad, PAGE_SIZE, SCIF_IOVA_START_PFN,
-			 SCIF_DMA_64BIT_PFN);
+	init_iova_domain(&rma->iovad, PAGE_SIZE, SCIF_IOVA_START_PFN);
 	spin_lock_init(&rma->tc_lock);
 	mutex_init(&rma->mmn_lock);
 	INIT_LIST_HEAD(&rma->reg_list);
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 844d723..6f037b2 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -101,7 +101,7 @@ struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
 	unsigned long pfn_hi);
 void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);
 void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
-	unsigned long start_pfn, unsigned long pfn_32bit);
+	unsigned long start_pfn);
 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
 void put_iova_domain(struct iova_domain *iovad);
 struct iova *split_and_remove_iova(struct iova_domain *iovad,
-- 
2.5.0

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#1613598 — [PATCH v2 5/7] iommu/iova: to optimize the allocation performance of dma64

Currently we always search free iova space for dma64 begin at the last
node of iovad rb-tree. In the worst case, there maybe too many nodes exist
at the tail, so that we should traverse many times for the first loop in
__alloc_and_insert_iova_range. As we traced, more than 10K times for the
case of iperf.

__alloc_and_insert_iova_range:
	......
	curr = __get_cached_rbnode(iovad, &limit_pfn);
		//--> return rb_last(&iovad->rbroot);
	while (curr) {
		......
		curr = rb_prev(curr);
	}

So add cached64_node to take the same effect as cached32_node, and add
the start_pfn boundary of dma64, to prevent a iova cross both dma32 and
dma64 area.
	|-------------------|------------------------------|
	|<--cached32_node-->|<--------cached64_node------->|
	|                   |
    start_pfn         dma_32bit_pfn + 1

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/iova.c | 46 +++++++++++++++++++++++++++-------------------
 include/linux/iova.h |  5 +++--
 2 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 87a9332..23abe84 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -37,10 +37,15 @@ insert_iova_boundary(struct iova_domain *iovad)
 {
 	struct iova *iova;
 	unsigned long start_pfn_32bit = iovad->start_pfn;
+	unsigned long start_pfn_64bit = iovad->dma_32bit_pfn + 1;
 
 	iova = reserve_iova(iovad, start_pfn_32bit, start_pfn_32bit);
 	BUG_ON(!iova);
 	iovad->cached32_node = &iova->node;
+
+	iova = reserve_iova(iovad, start_pfn_64bit, start_pfn_64bit);
+	BUG_ON(!iova);
+	iovad->cached64_node = &iova->node;
 }
 
 void
@@ -62,8 +67,8 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	init_iova_rcaches(iovad);
 
 	/*
-	 * Insert boundary nodes for dma32. So cached32_node can not be NULL in
-	 * future.
+	 * Insert boundary nodes for dma32 and dma64. So cached32_node and
+	 * cached64_node can not be NULL in future.
 	 */
 	insert_iova_boundary(iovad);
 }
@@ -75,10 +80,10 @@ __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
 	struct rb_node *cached_node;
 	struct rb_node *next_node;
 
-	if (*limit_pfn > iovad->dma_32bit_pfn)
-		return rb_last(&iovad->rbroot);
-	else
+	if (*limit_pfn <= iovad->dma_32bit_pfn)
 		cached_node = iovad->cached32_node;
+	else
+		cached_node = iovad->cached64_node;
 
 	next_node = rb_next(cached_node);
 	if (next_node) {
@@ -94,29 +99,32 @@ static void
 __cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
 {
 	struct iova *cached_iova;
+	struct rb_node **cached_node;
 
-	if (new->pfn_hi > iovad->dma_32bit_pfn)
-		return;
+	if (new->pfn_hi <= iovad->dma_32bit_pfn)
+		cached_node = &iovad->cached32_node;
+	else
+		cached_node = &iovad->cached64_node;
 
-	cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
+	cached_iova = rb_entry(*cached_node, struct iova, node);
 	if (new->pfn_lo <= cached_iova->pfn_lo)
-		iovad->cached32_node = rb_prev(&new->node);
+		*cached_node = rb_prev(&new->node);
 }
 
 static void
 __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
 {
 	struct iova *cached_iova;
-	struct rb_node *curr;
+	struct rb_node **cached_node;
 
-	curr = iovad->cached32_node;
-	cached_iova = rb_entry(curr, struct iova, node);
+	if (free->pfn_hi <= iovad->dma_32bit_pfn)
+		cached_node = &iovad->cached32_node;
+	else
+		cached_node = &iovad->cached64_node;
 
-	if (free->pfn_lo >= cached_iova->pfn_lo) {
-		/* only cache if it's below 32bit pfn */
-		if (free->pfn_hi <= iovad->dma_32bit_pfn)
-			iovad->cached32_node = rb_prev(&free->node);
-	}
+	cached_iova = rb_entry(*cached_node, struct iova, node);
+	if (free->pfn_lo >= cached_iova->pfn_lo)
+		*cached_node = rb_prev(&free->node);
 }
 
 /*
@@ -283,7 +291,7 @@ EXPORT_SYMBOL_GPL(iova_cache_put);
  * alloc_iova - allocates an iova
  * @iovad: - iova domain in question
  * @size: - size of page frames to allocate
- * @limit_pfn: - max limit address
+ * @limit_pfn: - max limit address(included)
  * @size_aligned: - set if size_aligned address range is required
  * This function allocates an iova in the range iovad->start_pfn to limit_pfn,
  * searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
@@ -402,7 +410,7 @@ EXPORT_SYMBOL_GPL(free_iova);
  * alloc_iova_fast - allocates an iova from rcache
  * @iovad: - iova domain in question
  * @size: - size of page frames to allocate
- * @limit_pfn: - max limit address
+ * @limit_pfn: - max limit address(included)
  * This function tries to satisfy an iova allocation from the rcache,
  * and falls back to regular allocation on failure.
 */
diff --git a/include/linux/iova.h b/include/linux/iova.h
index f27bb2c..844d723 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -40,10 +40,11 @@ struct iova_rcache {
 struct iova_domain {
 	spinlock_t	iova_rbtree_lock; /* Lock to protect update of rbtree */
 	struct rb_root	rbroot;		/* iova domain rbtree root */
-	struct rb_node	*cached32_node; /* Save last alloced node */
+	struct rb_node	*cached32_node; /* Save last alloced node, 32bits */
+	struct rb_node	*cached64_node; /* Save last alloced node, 64bits */
 	unsigned long	granule;	/* pfn granularity for this domain */
 	unsigned long	start_pfn;	/* Lower limit for this domain */
-	unsigned long	dma_32bit_pfn;
+	unsigned long	dma_32bit_pfn;	/* max dma32 limit address(included) */
 	struct iova_rcache rcaches[IOVA_RANGE_CACHE_MAX_SIZE];	/* IOVA range caches */
 };
 
-- 
2.5.0

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#1613599 — [PATCH v2 2/7] iommu/iova: cut down judgement times

Below judgement can only be satisfied at the last time, which produced 2N
judgements(suppose N times failed, 0 or 1 time successed) in vain.

if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
	return iova;
}

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/iova.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 8ba8b496..1c49969 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -312,15 +312,12 @@ private_find_iova(struct iova_domain *iovad, unsigned long pfn)
 	while (node) {
 		struct iova *iova = rb_entry(node, struct iova, node);
 
-		/* If pfn falls within iova's range, return iova */
-		if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
-			return iova;
-		}
-
 		if (pfn < iova->pfn_lo)
 			node = node->rb_left;
-		else if (pfn > iova->pfn_lo)
+		else if (pfn > iova->pfn_hi)
 			node = node->rb_right;
+		else
+			return iova;	/* pfn falls within iova's range */
 	}
 
 	return NULL;
-- 
2.5.0

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#1613600 — [PATCH v2 1/7] iommu/iova: fix incorrect variable types

Keep these four variables type consistent with the paramters of function
__alloc_and_insert_iova_range and the members of struct iova:

1. static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
		unsigned long size, unsigned long limit_pfn,

2. struct iova {
	unsigned long	pfn_hi;
	unsigned long	pfn_lo;

In fact, limit_pfn is most likely larger than 32 bits on DMA64.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/iova.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b7268a1..8ba8b496 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -104,8 +104,8 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
  * Computes the padding size required, to make the start address
  * naturally aligned on the power-of-two order of its size
  */
-static unsigned int
-iova_get_pad_size(unsigned int size, unsigned int limit_pfn)
+static unsigned long
+iova_get_pad_size(unsigned long size, unsigned long limit_pfn)
 {
 	return (limit_pfn + 1 - size) & (__roundup_pow_of_two(size) - 1);
 }
@@ -117,7 +117,7 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 	struct rb_node *prev, *curr = NULL;
 	unsigned long flags;
 	unsigned long saved_pfn;
-	unsigned int pad_size = 0;
+	unsigned long pad_size = 0;
 
 	/* Walk the tree backwards */
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
-- 
2.5.0

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