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From:   Claire Chang <tientzu@chromium.org>
To:     Rob Herring <robh+dt@kernel.org>, mpe@ellerman.id.au,
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Subject: [PATCH v15 08/12] swiotlb: Refactor swiotlb_tbl_unmap_single
Date:   Thu, 24 Jun 2021 23:55:22 +0800
Message-Id: <20210624155526.2775863-9-tientzu@chromium.org>
In-Reply-To: <20210624155526.2775863-1-tientzu@chromium.org>
References: <20210624155526.2775863-1-tientzu@chromium.org>
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Add a new function, swiotlb_release_slots, to make the code reusable for
supporting different bounce buffer pools.

Signed-off-by: Claire Chang <tientzu@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Will Deacon <will@kernel.org>
---
 kernel/dma/swiotlb.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index b41d16e92cf6..93752e752e76 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -557,27 +557,15 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
 	return tlb_addr;
 }
 
-/*
- * tlb_addr is the physical address of the bounce buffer to unmap.
- */
-void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
-			      size_t mapping_size, enum dma_data_direction dir,
-			      unsigned long attrs)
+static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
 {
-	struct io_tlb_mem *mem = hwdev->dma_io_tlb_mem;
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
 	unsigned long flags;
-	unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr);
+	unsigned int offset = swiotlb_align_offset(dev, tlb_addr);
 	int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
 	int nslots = nr_slots(mem->slots[index].alloc_size + offset);
 	int count, i;
 
-	/*
-	 * First, sync the memory before unmapping the entry
-	 */
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
-		swiotlb_bounce(hwdev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
-
 	/*
 	 * Return the buffer to the free list by setting the corresponding
 	 * entries to indicate the number of contiguous entries available.
@@ -612,6 +600,23 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 	spin_unlock_irqrestore(&mem->lock, flags);
 }
 
+/*
+ * tlb_addr is the physical address of the bounce buffer to unmap.
+ */
+void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr,
+			      size_t mapping_size, enum dma_data_direction dir,
+			      unsigned long attrs)
+{
+	/*
+	 * First, sync the memory before unmapping the entry
+	 */
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
+		swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+
+	swiotlb_release_slots(dev, tlb_addr);
+}
+
 void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr,
 		size_t size, enum dma_data_direction dir)
 {
-- 
2.32.0.288.g62a8d224e6-goog