[PATCH rdma-rc] RDMA/umem: Fix ib_umem_find_best_pgsz()

[Leon Romanovsky <leon@kernel.org>]

From: Artemy Kovalyov <artemyko@mellanox.com>

Except for the last entry, the ending iova alignment sets the maximum
possible page size as the low bits of the iova must be zero when
starting the next chunk.

Fixes: 4a35339958f1 ("RDMA/umem: Add API to find best driver supported page size in an MR")
Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
 drivers/infiniband/core/umem.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 933dc1aeed5f..82455a1392f1 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -166,10 +166,13 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
 		 * for any address.
 		 */
 		mask |= (sg_dma_address(sg) + pgoff) ^ va;
-		if (i && i != (umem->nmap - 1))
-			/* restrict by length as well for interior SGEs */
-			mask |= sg_dma_len(sg);
 		va += sg_dma_len(sg) - pgoff;
+		/* Except for the last entry, the ending iova alignment sets
+		 * the maximum possible page size as the low bits of the iova
+		 * must be zero when starting the next chunk.
+		 */
+		if (i != (umem->nmap - 1))
+			mask |= va;
 		pgoff = 0;
 	}
 	best_pg_bit = rdma_find_pg_bit(mask, pgsz_bitmap);
--
2.24.1