[PATCH 5.15 632/917] RDMA/core: Set sgtable nents when using ib_dma_virt_map_sg()

[Greg Kroah-Hartman]

From: Logan Gunthorpe <logang@xxxxxxxxxxxx>

[ Upstream commit ac0fffa0859b8e1e991939663b3ebdd80bf979e6 ]

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.

Fixes: 79fbd3e1241c ("RDMA: Use the sg_table directly and remove the opencoded version from umem")
Link: https://lore.kernel.org/r/20211013165942.89806-1-logang@xxxxxxxxxxxx
Reported-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Tested-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 4b50d9a3018a6..4ba642fc8a19a 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);
-- 
2.33.0