linux-kernel - [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator

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Message-ID: <1616160348-29451-2-git-send-email-john.garry@huawei.com>
Date:   Fri, 19 Mar 2021 21:25:43 +0800
From:   John Garry <john.garry@...wei.com>
To:     <joro@...tes.org>, <will@...nel.org>, <jejb@...ux.ibm.com>,
        <martin.petersen@...cle.com>, <hch@....de>,
        <m.szyprowski@...sung.com>, <robin.murphy@....com>
CC:     <iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-scsi@...r.kernel.org>, <linuxarm@...wei.com>,
        John Garry <john.garry@...wei.com>
Subject: [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator

Move the IOVA size power-of-2 rcache roundup into the IOVA allocator.

This is to eventually make it possible to be able to configure the upper
limit of the IOVA rcache range.

Signed-off-by: John Garry <john.garry@...wei.com>
---
 drivers/iommu/dma-iommu.c |  8 ------
 drivers/iommu/iova.c      | 51 ++++++++++++++++++++++++++-------------
 2 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index af765c813cc8..15b7270a5c2a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -429,14 +429,6 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
 
 	shift = iova_shift(iovad);
 	iova_len = size >> shift;
-	/*
-	 * Freeing non-power-of-two-sized allocations back into the IOVA caches
-	 * will come back to bite us badly, so we have to waste a bit of space
-	 * rounding up anything cacheable to make sure that can't happen. The
-	 * order of the unadjusted size will still match upon freeing.
-	 */
-	if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
-		iova_len = roundup_pow_of_two(iova_len);
 
 	dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit);
 
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index e6e2fa85271c..e62e9e30b30c 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -179,7 +179,7 @@ iova_insert_rbtree(struct rb_root *root, struct iova *iova,
 
 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 iova *new, bool size_aligned, bool fast)
 {
 	struct rb_node *curr, *prev;
 	struct iova *curr_iova;
@@ -188,6 +188,15 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
 	unsigned long align_mask = ~0UL;
 	unsigned long high_pfn = limit_pfn, low_pfn = iovad->start_pfn;
 
+	/*
+	 * Freeing non-power-of-two-sized allocations back into the IOVA caches
+	 * will come back to bite us badly, so we have to waste a bit of space
+	 * rounding up anything cacheable to make sure that can't happen. The
+	 * order of the unadjusted size will still match upon freeing.
+	 */
+	if (fast && size < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
+		size = roundup_pow_of_two(size);
+
 	if (size_aligned)
 		align_mask <<= fls_long(size - 1);
 
@@ -288,21 +297,10 @@ void iova_cache_put(void)
 }
 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
- * @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
- * flag is set then the allocated address iova->pfn_lo will be naturally
- * aligned on roundup_power_of_two(size).
- */
-struct iova *
-alloc_iova(struct iova_domain *iovad, unsigned long size,
+static struct iova *
+__alloc_iova(struct iova_domain *iovad, unsigned long size,
 	unsigned long limit_pfn,
-	bool size_aligned)
+	bool size_aligned, bool fast)
 {
 	struct iova *new_iova;
 	int ret;
@@ -312,7 +310,7 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
 		return NULL;
 
 	ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn + 1,
-			new_iova, size_aligned);
+			new_iova, size_aligned, fast);
 
 	if (ret) {
 		free_iova_mem(new_iova);
@@ -321,6 +319,25 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
 
 	return new_iova;
 }
+
+/**
+ * alloc_iova - allocates an iova
+ * @iovad: - iova domain in question
+ * @size: - size of page frames to allocate
+ * @limit_pfn: - max limit address
+ * @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
+ * flag is set then the allocated address iova->pfn_lo will be naturally
+ * aligned on roundup_power_of_two(size).
+ */
+struct iova *
+alloc_iova(struct iova_domain *iovad, unsigned long size,
+	unsigned long limit_pfn,
+	bool size_aligned)
+{
+	return __alloc_iova(iovad, size, limit_pfn, size_aligned, false);
+}
 EXPORT_SYMBOL_GPL(alloc_iova);
 
 static struct iova *
@@ -433,7 +450,7 @@ alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
 		return iova_pfn;
 
 retry:
-	new_iova = alloc_iova(iovad, size, limit_pfn, true);
+	new_iova = __alloc_iova(iovad, size, limit_pfn, true, true);
 	if (!new_iova) {
 		unsigned int cpu;
 
-- 
2.26.2