[PATCH] swiotlb: add kernel error message to track iobtlb overflow buffer usage

[Shuah Khan <shuah.khan@hp.com>]

Add kernel error message to track iotlb overflow buffer triggers to understand
how often the overflow buffer gets used.

Signed-off-by: Shuah Khan <shuah.khan@hp.com>
---
 lib/swiotlb.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 45bc1f8..597d7b9 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -682,6 +682,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	if (!map) {
 		swiotlb_full(dev, size, dir, 1);
 		map = io_tlb_overflow_buffer;
+		dev_err(dev, "SWIOTLB is full. Mapping overflow buffer.\n");
 	}
 
 	dev_addr = swiotlb_virt_to_bus(dev, map);
-- 
1.7.9.5