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-rw-r--r--kernel/dma/swiotlb.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9cb21259cb0b..c873f9cc2146 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev)
{
return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
}
+
+bool is_swiotlb_active(void)
+{
+ /*
+ * When SWIOTLB is initialized, even if io_tlb_start points to physical
+ * address zero, io_tlb_end surely doesn't.
+ */
+ return io_tlb_end != 0;
+}