swiotlb: factor out a nr_slots helper

Factor out a helper to find the number of slots for a given size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jianxiong Gao <jxgao@google.com>
Tested-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 7705821..9492219 100644 (file)
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -194,6 +194,11 @@ static inline unsigned long io_tlb_offset(unsigned long val)
        return val & (IO_TLB_SEGSIZE - 1);
 }
 
+static inline unsigned long nr_slots(u64 val)
+{
+       return DIV_ROUND_UP(val, IO_TLB_SIZE);
+}
+
 /*
  * Early SWIOTLB allocation may be too early to allow an architecture to
  * perform the desired operations.  This function allows the architecture to
@@ -493,20 +498,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
 
        tbl_dma_addr &= mask;
 
-       offset_slots = ALIGN(tbl_dma_addr, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+       offset_slots = nr_slots(tbl_dma_addr);
 
        /*
         * Carefully handle integer overflow which can occur when mask == ~0UL.
         */
        max_slots = mask + 1
-                   ? ALIGN(mask + 1, IO_TLB_SIZE) >> IO_TLB_SHIFT
+                   ? nr_slots(mask + 1)
                    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
 
        /*
         * For mappings greater than or equal to a page, we limit the stride
         * (and hence alignment) to a page size.
         */
-       nslots = ALIGN(alloc_size, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+       nslots = nr_slots(alloc_size);
        if (alloc_size >= PAGE_SIZE)
                stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
        else
@@ -602,7 +607,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
                              enum dma_data_direction dir, unsigned long attrs)
 {
        unsigned long flags;
-       int i, count, nslots = ALIGN(alloc_size, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+       int i, count, nslots = nr_slots(alloc_size);
        int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
        phys_addr_t orig_addr = io_tlb_orig_addr[index];