[PATCH rdma-next 1/5] RDMA/uverbs: Tidy input validation of ib_uverbs_rereg_mr()

[Leon Romanovsky <leon@kernel.org>]

From: Jason Gunthorpe <jgg@nvidia.com>

Unknown flags should be EOPNOTSUPP, only zero flags is EINVAL. Flags is
actually the rereg action to perform.

The checking of the start/hca_va/etc is also redundant and ib_umem_get()
does these checks and returns proper error codes.

Fixes: 7e6edb9b2e0b ("IB/core: Add user MR re-registration support")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/uverbs_cmd.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index a43c3d6d92a2..c0b4aaf724de 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -781,13 +781,15 @@ static int ib_uverbs_rereg_mr(struct uverbs_attr_bundle *attrs)
 	if (ret)
 		return ret;

-	if (cmd.flags & ~IB_MR_REREG_SUPPORTED || !cmd.flags)
+	if (!cmd.flags)
 		return -EINVAL;

+	if (cmd.flags & ~IB_MR_REREG_SUPPORTED)
+		return -EOPNOTSUPP;
+
 	if ((cmd.flags & IB_MR_REREG_TRANS) &&
-	    (!cmd.start || !cmd.hca_va || 0 >= cmd.length ||
-	     (cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK)))
-			return -EINVAL;
+	    (cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK))
+		return -EINVAL;

 	uobj = uobj_get_write(UVERBS_OBJECT_MR, cmd.mr_handle, attrs);
 	if (IS_ERR(uobj))
--
2.28.0