xprtrdma: Stack relief in fmr_op_map()

fmr_op_map() declares a 64 element array of u64 in automatic
storage. This is 512 bytes (8 * 64) on the stack.

Instead, when FMR memory registration is in use, pre-allocate a
physaddr array for each rpcrdma_mw.

This is a pre-requisite for increasing the r/wsize maximum for
FMR on platforms with 4KB pages.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index df92884400c4..110d685b4ac5 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -206,9 +206,14 @@ struct rpcrdma_frmr {
 	struct rpcrdma_xprt		*fr_xprt;
 };
 
+struct rpcrdma_fmr {
+	struct ib_fmr		*fmr;
+	u64			*physaddrs;
+};
+
 struct rpcrdma_mw {
 	union {
-		struct ib_fmr		*fmr;
+		struct rpcrdma_fmr	fmr;
 		struct rpcrdma_frmr	frmr;
 	} r;
 	void			(*mw_sendcompletion)(struct ib_wc *);