swiotlb: Make swiotlb_{alloc,free}_buffer depend on CONFIG_DMA_DIRECT_OPS

Otherwise this causes unused symbol warnings for configs that build
swiotlb.c only for use by xen-swiotlb.c and that don't otherwise select
CONFIG_DMA_DIRECT_OPS, which is possible on arm.

Fixes: 16e73adbca76 ("dma/swiotlb: Remove swiotlb_{alloc,free}_coherent()")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: iommu@lists.linux-foundation.org
Cc: konrad.wilk@oracle.com
Link: https://lkml.kernel.org/r/20180323174930.17767-1-hch@lst.de

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 15954b86f09e2c64a996a0bb2795eb501c41d375..47aeb04c1997bf45c943985cfda6f08ea716b92d 100644 (file)
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -692,6 +692,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
        }
 }
 
+#ifdef CONFIG_DMA_DIRECT_OPS
 static inline bool dma_coherent_ok(struct device *dev, dma_addr_t addr,
                size_t size)
 {
@@ -763,6 +764,7 @@ static bool swiotlb_free_buffer(struct device *dev, size_t size,
                                 DMA_ATTR_SKIP_CPU_SYNC);
        return true;
 }
+#endif
 
 static void
 swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,