[PATCH v6 10/15] swiotlb: Refactor swiotlb_tbl_unmap_single

[Claire Chang <tientzu@xxxxxxxxxxxx>]

Add a new function, release_slots, to make the code reusable for supporting
different bounce buffer pools, e.g. restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
---
 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 ef04d8f7708f..fa11787e4b95 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -550,27 +550,15 @@ 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 release_slots(struct device *dev, phys_addr_t tlb_addr)
 {
-       struct io_tlb_mem *mem = get_io_tlb_mem(hwdev);
+       struct io_tlb_mem *mem = get_io_tlb_mem(dev);
        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.
@@ -605,6 +593,23 @@ 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);
+
+       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)
 {
-- 
2.31.1.607.g51e8a6a459-goog