Merge tag 'nfs-rdma-for-4.16-2' of git://git.linux-nfs.org/projects/anna/linux-nfs

NFS-over-RDMA client fixes for Linux 4.16 #2

Stable fixes:
- Fix calculating ri_max_send_sges, which can oops if max_sge is too small
- Fix a BUG after device removal if freed resources haven't been allocated yet

Author: trondmypd

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -143,7 +143,7 @@ static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
 	if (xdr->page_len) {
 		remaining = xdr->page_len;
 		offset = offset_in_page(xdr->page_base);
-		count = 0;
+		count = RPCRDMA_MIN_SEND_SGES;
 		while (remaining) {
 			remaining -= min_t(unsigned int,
 					   PAGE_SIZE - offset, remaining);

net/sunrpc/xprtrdma/verbs.c

@@ -505,7 +505,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 		pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);
 		return -ENOMEM;
 	}
-	ia->ri_max_send_sges = max_sge - RPCRDMA_MIN_SEND_SGES;
+	ia->ri_max_send_sges = max_sge;
 
 	if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
 		dprintk("RPC:       %s: insufficient wqe's available\n",
@@ -1502,6 +1502,9 @@ __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
 static void
 rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb)
 {
+	if (!rb)
+		return;
+
 	if (!rpcrdma_regbuf_is_mapped(rb))
 		return;
 
@@ -1517,9 +1520,6 @@ rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb)
 void
 rpcrdma_free_regbuf(struct rpcrdma_regbuf *rb)
 {
-	if (!rb)
-		return;
-
 	rpcrdma_dma_unmap_regbuf(rb);
 	kfree(rb);
 }