[PATCH RFT] net: Fix Neptune ethernet driver to check dma mapping error

Request for testing, since I don't have the hardware to test.

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Fix Neptune ethernet driver to check dma mapping error after map_page()
interface returns.

Signed-off-by: Shuah Khan <redacted>
Cc: <redacted>
---
 drivers/net/ethernet/sun/niu.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index 8c726b7..60d5c03 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c

@@ -3335,6 +3335,10 @@ static int niu_rbr_add_page(struct niu *np, struct rx_ring_info *rp,
 
 	addr = np->ops->map_page(np->device, page, 0,
 				 PAGE_SIZE, DMA_FROM_DEVICE);
+	if (!addr) {
+		__free_page(page);
+		return -ENOMEM;
+	}
 
 	niu_hash_page(rp, page, addr);
 	if (rp->rbr_blocks_per_page > 1)

-- 
1.7.9.5