[PATCH] RDMA/core: Set sgtable nents when using ib_dma_virt_map_sg()

[Logan Gunthorpe]

ib_dma_map_sgtable_attrs() should be mapping the sgls and setting nents
but the ib_uses_virt_dma() path falls back to ib_dma_virt_map_sg()
which will not set the nents in the sgtable.

Check the return value (per the map_sg calling convention) and set
sgt->nents appropriately on success.

Link: https://lore.kernel.org/all/996fa723-18ef-d35b-c565-c9cb9dc2d5e1@xxxxxxx/T/#u
Reported-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Tested-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 include/rdma/ib_verbs.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 4b50d9a3018a..4ba642fc8a19 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -4097,8 +4097,13 @@ static inline int ib_dma_map_sgtable_attrs(struct ib_device *dev,
 					   enum dma_data_direction direction,
 					   unsigned long dma_attrs)
 {
+	int nents;
+
 	if (ib_uses_virt_dma(dev)) {
-		ib_dma_virt_map_sg(dev, sgt->sgl, sgt->orig_nents);
+		nents = ib_dma_virt_map_sg(dev, sgt->sgl, sgt->orig_nents);
+		if (!nents)
+			return -EIO;
+		sgt->nents = nents;
 		return 0;
 	}
 	return dma_map_sgtable(dev->dma_device, sgt, direction, dma_attrs);

base-commit: 2a152512a155aaf27c3e67834ffafaed9525a7b5
-- 
2.30.2