linux-kernel - [PATCH v3 02/10] swiotlb: Factor out slot allocation and free

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Date:   Sun, 21 Apr 2019 09:17:11 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     David Woodhouse <dwmw2@...radead.org>,
        Joerg Roedel <joro@...tes.org>
Cc:     ashok.raj@...el.com, jacob.jun.pan@...el.com, alan.cox@...el.com,
        kevin.tian@...el.com, mika.westerberg@...ux.intel.com,
        pengfei.xu@...el.com,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v3 02/10] swiotlb: Factor out slot allocation and free

This moves slot allocation and free code into two common
functions in order to avoid code duplication. There's no
functional change.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Christoph Hellwig <hch@....de>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Robin Murphy <robin.murphy@....com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 kernel/dma/swiotlb.c | 72 +++++++++++++++++++++++++++++---------------
 1 file changed, 47 insertions(+), 25 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 53012db1e53c..173122d16b7f 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -439,11 +439,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
 	}
 }
 
-phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
-				   dma_addr_t tbl_dma_addr,
-				   phys_addr_t orig_addr, size_t size,
-				   enum dma_data_direction dir,
-				   unsigned long attrs)
+static phys_addr_t
+swiotlb_tbl_alloc_tlb(struct device *hwdev, dma_addr_t tbl_dma_addr,
+		      phys_addr_t orig_addr, size_t size)
 {
 	unsigned long flags;
 	phys_addr_t tlb_addr;
@@ -539,8 +537,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 
 not_found:
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
-	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
-		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
 	return DMA_MAPPING_ERROR;
 found:
 	io_tlb_used += nslots;
@@ -553,32 +549,16 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 	 */
 	for (i = 0; i < nslots; i++)
 		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
-		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
 
 	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 size, enum dma_data_direction dir,
-			      unsigned long attrs)
+static void
+swiotlb_tbl_free_tlb(struct device *hwdev, phys_addr_t tlb_addr, size_t size)
 {
 	unsigned long flags;
 	int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-	phys_addr_t orig_addr = io_tlb_orig_addr[index];
-
-	/*
-	 * First, sync the memory before unmapping the entry
-	 */
-	if (orig_addr != INVALID_PHYS_ADDR &&
-	    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
-		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
 
 	/*
 	 * Return the buffer to the free list by setting the corresponding
@@ -610,6 +590,48 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 }
 
+phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
+				   dma_addr_t tbl_dma_addr,
+				   phys_addr_t orig_addr, size_t size,
+				   enum dma_data_direction dir,
+				   unsigned long attrs)
+{
+	phys_addr_t tlb_addr;
+
+	tlb_addr = swiotlb_tbl_alloc_tlb(hwdev, tbl_dma_addr, orig_addr, size);
+	if (tlb_addr == DMA_MAPPING_ERROR) {
+		if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
+			dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n",
+				 size);
+	} else if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+		   (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) {
+		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+	}
+
+	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 size, enum dma_data_direction dir,
+			      unsigned long attrs)
+{
+	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = io_tlb_orig_addr[index];
+
+	/*
+	 * First, sync the memory before unmapping the entry
+	 */
+	if (orig_addr != INVALID_PHYS_ADDR &&
+	    !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+		swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+
+	swiotlb_tbl_free_tlb(hwdev, tlb_addr, size);
+}
+
 void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
 			     size_t size, enum dma_data_direction dir,
 			     enum dma_sync_target target)
-- 
2.17.1