[PATCH] dma-mapping: direct: fix missing mapping for THRU_HOST_BRIDGE segments

[lirongqing]

From: Li RongQing <lirongqing@xxxxxxxxx>

In dma_direct_map_sg(), the case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE
incorrectly used 'break' instead of falling through to MAP_NONE.
As a result, segments traversing the host bridge skipped the required
dma_direct_map_phys() call entirely, leaving sg->dma_address
uninitialized and leading to DMA failures. Fix this by using
'fallthrough;'.

Fixes: a25e7962db0d79 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers")
Reviewed-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
 kernel/dma/direct.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 583c592..4391b79 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -476,7 +476,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
 			 * must be mapped with CPU physical address and not PCI
 			 * bus addresses.
 			 */
-			break;
+			fallthrough;
 		case PCI_P2PDMA_MAP_NONE:
 			need_sync = true;
 			sg->dma_address = dma_direct_map_phys(dev, sg_phys(sg),
-- 
2.9.4