xprtrdma: Eliminate per-transport "max pages"
To support device hotplug and migrating a connection between devices
of different capabilities, we have to guarantee that all in-kernel
devices can support the same max NFS payload size (1 megabyte).
This means that possibly one or two in-tree devices are no longer
supported for NFS/RDMA because they cannot support 1MB rsize/wsize.
The only one I confirmed was cxgb3, but it has already been removed
from the kernel.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 859c301..032a896 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -178,7 +178,7 @@ int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr)
* ep->rep_attr.cap.max_send_wr
* ep->rep_attr.cap.max_recv_wr
* ep->rep_max_requests
- * ia->ri_max_segs
+ * ia->ri_max_rdma_segs
*
* And these FRWR-related fields:
* ia->ri_max_frwr_depth
@@ -209,14 +209,12 @@ int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep)
* capability, but perform optimally when the MRs are not larger
* than a page.
*/
- if (attrs->max_sge_rd > 1)
+ if (attrs->max_sge_rd > RPCRDMA_MAX_HDR_SEGS)
ia->ri_max_frwr_depth = attrs->max_sge_rd;
else
ia->ri_max_frwr_depth = attrs->max_fast_reg_page_list_len;
if (ia->ri_max_frwr_depth > RPCRDMA_MAX_DATA_SEGS)
ia->ri_max_frwr_depth = RPCRDMA_MAX_DATA_SEGS;
- dprintk("RPC: %s: max FR page list depth = %u\n",
- __func__, ia->ri_max_frwr_depth);
/* Add room for frwr register and invalidate WRs.
* 1. FRWR reg WR for head
@@ -260,33 +258,25 @@ int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep)
ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
- ia->ri_max_segs =
+ ia->ri_max_rdma_segs =
DIV_ROUND_UP(RPCRDMA_MAX_DATA_SEGS, ia->ri_max_frwr_depth);
/* Reply chunks require segments for head and tail buffers */
- ia->ri_max_segs += 2;
- if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS)
- ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS;
+ ia->ri_max_rdma_segs += 2;
+ if (ia->ri_max_rdma_segs > RPCRDMA_MAX_HDR_SEGS)
+ ia->ri_max_rdma_segs = RPCRDMA_MAX_HDR_SEGS;
+
+ /* Ensure the underlying device is capable of conveying the
+ * largest r/wsize NFS will ask for. This guarantees that
+ * failing over from one RDMA device to another will not
+ * break NFS I/O.
+ */
+ if ((ia->ri_max_rdma_segs * ia->ri_max_frwr_depth) < RPCRDMA_MAX_SEGS)
+ return -ENOMEM;
+
return 0;
}
/**
- * frwr_maxpages - Compute size of largest payload
- * @r_xprt: transport
- *
- * Returns maximum size of an RPC message, in pages.
- *
- * FRWR mode conveys a list of pages per chunk segment. The
- * maximum length of that list is the FRWR page list depth.
- */
-size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt)
-{
- struct rpcrdma_ia *ia = &r_xprt->rx_ia;
-
- return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
- (ia->ri_max_segs - 2) * ia->ri_max_frwr_depth);
-}
-
-/**
* frwr_map - Register a memory region
* @r_xprt: controlling transport
* @seg: memory region co-ordinates