[PATCH] RDMA/umem: updated bug fix in error handling path

From: john . hubbard
Date: Tue Mar 05 2019 - 21:00:29 EST


From: John Hubbard <jhubbard@xxxxxxxxxx>

The previous attempted bug fix overlooked the fact that
ib_umem_odp_map_dma_single_page() was doing a put_page()
upon hitting an error. So there was not really a bug there.

Therefore, this reverts the off-by-one change, but
keeps the change to use release_pages() in the error path.

Fixes: commit xxxxxxxxxxxx ("RDMA/umem: minor bug fix in error handling path")
Suggested-by: Artemy Kovalyov <artemyko@xxxxxxxxxxxx>

Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: linux-rdma@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
drivers/infiniband/core/umem_odp.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index d45735b02e07..c9cafaa080e7 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -686,10 +686,13 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,

if (ret < 0) {
/*
- * Release pages, starting at the the first page
- * that experienced an error.
+ * Release pages, remembering that the first page
+ * to hit an error was already released by
+ * ib_umem_odp_map_dma_single_page().
*/
- release_pages(&local_page_list[j], npages - j);
+ if (npages - (j + 1) > 0)
+ release_pages(&local_page_list[j+1],
+ npages - (j + 1));
break;
}
}
--
2.21.0