RDS: Add GET_MR_FOR_DEST sockopt

RDS currently supports a GET_MR sockopt to establish a
memory region (MR) for a chunk of memory. However, the fastreg
method ties a MR to a particular destination. The GET_MR_FOR_DEST
sockopt allows the remote machine to be specified, and thus
support for fastreg (aka FRWRs).

Note that this patch does *not* do all of this - it simply
implements the new sockopt in terms of the old one, so applications
can begin to use the new sockopt in preparation for cutover to
FRWRs.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index a202e5b36079..2b978dc6e75d 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -265,6 +265,9 @@ static int rds_setsockopt(struct socket *sock, int level, int optname,
         case RDS_GET_MR:
                 ret = rds_get_mr(rs, optval, optlen);
                 break;
+        case RDS_GET_MR_FOR_DEST:
+                ret = rds_get_mr_for_dest(rs, optval, optlen);
+                break;
         case RDS_FREE_MR:
                 ret = rds_free_mr(rs, optval, optlen);
                 break;