[PATCH v5 5/5] iova: Add iova_len argument to iova_domain_init_rcaches()

[John Garry]

Add max opt argument to iova_domain_init_rcaches(), and use it to set the
rcaches range.

Also fix up all users to set this value (at 0, meaning use default),
including a wrapper for that, iova_domain_init_rcaches_default().

For dma-iommu.c we derive the iova_len argument from the IOMMU group
max opt DMA size.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/iommu/dma-iommu.c            | 15 ++++++++++++++-
 drivers/iommu/iova.c                 | 19 ++++++++++++++++---
 drivers/vdpa/vdpa_user/iova_domain.c |  4 ++--
 include/linux/iova.h                 |  3 ++-
 4 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 908272f0153e..7afa2226c6bd 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -525,6 +525,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	unsigned long order, base_pfn;
 	struct iova_domain *iovad;
+	size_t max_opt_dma_size;
+	unsigned long iova_len = 0;
 	int ret;
 
 	if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
@@ -560,7 +562,18 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 	}
 
 	init_iova_domain(iovad, 1UL << order, base_pfn);
-	ret = iova_domain_init_rcaches(iovad);
+
+	max_opt_dma_size = iommu_group_get_max_opt_dma_size(dev->iommu_group);
+	if (max_opt_dma_size) {
+		unsigned long shift = __ffs(1UL << order);
+
+		iova_len = roundup_pow_of_two(max_opt_dma_size);
+		iova_len >>= shift;
+		if (!iova_len)
+			iova_len = 1;
+	}
+
+	ret = iova_domain_init_rcaches(iovad, iova_len);
 	if (ret)
 		return ret;
 
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index f6eb93c737cb..f05aae044e25 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -705,12 +705,20 @@ static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
 	mag->pfns[mag->size++] = pfn;
 }
 
-int iova_domain_init_rcaches(struct iova_domain *iovad)
+static unsigned long iova_len_to_rcache_max(unsigned long iova_len)
+{
+	return order_base_2(iova_len) + 1;
+}
+
+int iova_domain_init_rcaches(struct iova_domain *iovad, unsigned long iova_len)
 {
 	unsigned int cpu;
 	int i, ret;
 
-	iovad->rcache_max_size = 6; /* Arbitrarily high default */
+	if (iova_len)
+		iovad->rcache_max_size = iova_len_to_rcache_max(iova_len);
+	else
+		iovad->rcache_max_size = 6; /* Arbitrarily high default */
 
 	iovad->rcaches = kcalloc(iovad->rcache_max_size,
 				 sizeof(struct iova_rcache),
@@ -754,7 +762,12 @@ int iova_domain_init_rcaches(struct iova_domain *iovad)
 	free_iova_rcaches(iovad);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(iova_domain_init_rcaches);
+
+int iova_domain_init_rcaches_default(struct iova_domain *iovad)
+{
+	return iova_domain_init_rcaches(iovad, 0);
+}
+EXPORT_SYMBOL_GPL(iova_domain_init_rcaches_default);
 
 /*
  * Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 22f7d43f8a68..74471bc463ec 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -514,12 +514,12 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
 	spin_lock_init(&domain->iotlb_lock);
 	init_iova_domain(&domain->stream_iovad,
 			PAGE_SIZE, IOVA_START_PFN);
-	ret = iova_domain_init_rcaches(&domain->stream_iovad);
+	ret = iova_domain_init_rcaches_default(&domain->stream_iovad);
 	if (ret)
 		goto err_iovad_stream;
 	init_iova_domain(&domain->consistent_iovad,
 			PAGE_SIZE, bounce_pfns);
-	ret = iova_domain_init_rcaches(&domain->consistent_iovad);
+	ret = iova_domain_init_rcaches_default(&domain->consistent_iovad);
 	if (ret)
 		goto err_iovad_consistent;
 
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 02f7222fa85a..56281434ce0c 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -95,7 +95,8 @@ struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
 	unsigned long pfn_hi);
 void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	unsigned long start_pfn);
-int iova_domain_init_rcaches(struct iova_domain *iovad);
+int iova_domain_init_rcaches(struct iova_domain *iovad, unsigned long iova_len);
+int iova_domain_init_rcaches_default(struct iova_domain *iovad);
 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
 void put_iova_domain(struct iova_domain *iovad);
 #else
-- 
2.26.2