rdma: Add an option to query,set net namespace sharing sys parameter

Enrich rdmatool with an option to query rdma subsystem parameter
whether rdma devices are shared among multiple network namespaces
or exclusive to single network namespace.

rdma tool command examples and output.

$ rdma system show
netns shared

$ rdma system set netns exclusive

$ rdma system show
netns exclusive

Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: David Ahern <dsahern@gmail.com>

rdma/Makefile

@@ -7,7 +7,7 @@ ifeq ($(HAVE_MNL),y)
 CFLAGS += -I./include/uapi/
 
 RDMA_OBJ = rdma.o utils.o dev.o link.o res.o res-pd.o res-mr.o res-cq.o \
-	   res-cmid.o res-qp.o
+	   res-cmid.o res-qp.o sys.o
 
 TARGETS += rdma
 endif

rdma/rdma.c

@@ -11,7 +11,7 @@ static void help(char *name)
 {
 	pr_out("Usage: %s [ OPTIONS ] OBJECT { COMMAND | help }\n"
 	       "       %s [ -f[orce] ] -b[atch] filename\n"
-	       "where  OBJECT := { dev | link | resource | help }\n"
+	       "where  OBJECT := { dev | link | resource | system | help }\n"
 	       "       OPTIONS := { -V[ersion] | -d[etails] | -j[son] | -p[retty]}\n", name, name);
 }
 
@@ -29,6 +29,7 @@ static int rd_cmd(struct rd *rd, int argc, char **argv)
 		{ "dev",	cmd_dev },
 		{ "link",	cmd_link },
 		{ "resource",	cmd_res },
+		{ "system",	cmd_sys },
 		{ 0 }
 	};
 

rdma/rdma.h

@@ -93,6 +93,7 @@ char *rd_argv(struct rd *rd);
 int cmd_dev(struct rd *rd);
 int cmd_link(struct rd *rd);
 int cmd_res(struct rd *rd);
+int cmd_sys(struct rd *rd);
 int rd_exec_cmd(struct rd *rd, const struct rd_cmd *c, const char *str);
 int rd_exec_dev(struct rd *rd, int (*cb)(struct rd *rd));
 int rd_exec_require_dev(struct rd *rd, int (*cb)(struct rd *rd));

rdma/sys.c

@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * sys.c	RDMA tool
+ */
+
+#include "rdma.h"
+
+static int sys_help(struct rd *rd)
+{
+	pr_out("Usage: %s system show [ netns ]\n", rd->filename);
+	pr_out("       %s system set netns { shared | exclusive }\n", rd->filename);
+	return 0;
+}
+
+static const char *netns_modes_str[] = {
+	"exclusive",
+	"shared",
+};
+
+static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nlattr *tb[RDMA_NLDEV_ATTR_MAX] = {};
+	struct rd *rd = data;
+
+	mnl_attr_parse(nlh, 0, rd_attr_cb, tb);
+
+	if (tb[RDMA_NLDEV_SYS_ATTR_NETNS_MODE]) {
+		const char *mode_str;
+		uint8_t netns_mode;
+
+		netns_mode =
+			mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_NETNS_MODE]);
+
+		if (netns_mode <= ARRAY_SIZE(netns_modes_str))
+			mode_str = netns_modes_str[netns_mode];
+		else
+			mode_str = "unknown";
+
+		if (rd->json_output)
+			jsonw_string_field(rd->jw, "netns", mode_str);
+		else
+			pr_out("netns %s\n", mode_str);
+	}
+	return MNL_CB_OK;
+}
+
+static int sys_show_no_args(struct rd *rd)
+{
+	uint32_t seq;
+	int ret;
+
+	rd_prepare_msg(rd, RDMA_NLDEV_CMD_SYS_GET,
+		       &seq, (NLM_F_REQUEST | NLM_F_ACK));
+	ret = rd_send_msg(rd);
+	if (ret)
+		return ret;
+
+	return rd_recv_msg(rd, sys_show_parse_cb, rd, seq);
+}
+
+static int sys_show(struct rd *rd)
+{
+	const struct rd_cmd cmds[] = {
+		{ NULL,		sys_show_no_args},
+		{ "netns",	sys_show_no_args},
+		{ 0 }
+	};
+
+	return rd_exec_cmd(rd, cmds, "parameter");
+}
+
+static int sys_set_netns_cmd(struct rd *rd, bool enable)
+{
+	uint32_t seq;
+
+	rd_prepare_msg(rd, RDMA_NLDEV_CMD_SYS_SET,
+		       &seq, (NLM_F_REQUEST | NLM_F_ACK));
+	mnl_attr_put_u8(rd->nlh, RDMA_NLDEV_SYS_ATTR_NETNS_MODE, enable);
+
+	return rd_sendrecv_msg(rd, seq);
+}
+
+static bool sys_valid_netns_cmd(const char *cmd)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(netns_modes_str); i++) {
+		if (!strcmp(cmd, netns_modes_str[i]))
+			return true;
+	}
+	return false;
+}
+
+static int sys_set_netns_args(struct rd *rd)
+{
+	bool cmd;
+
+	if (rd_no_arg(rd) || !sys_valid_netns_cmd(rd_argv(rd))) {
+		pr_err("valid options are: { shared | exclusive }\n");
+		return -EINVAL;
+	}
+
+	cmd = (strcmp(rd_argv(rd), "shared") == 0) ? true : false;
+
+	return sys_set_netns_cmd(rd, cmd);
+}
+
+static int sys_set_help(struct rd *rd)
+{
+	pr_out("Usage: %s system set [PARAM] value\n", rd->filename);
+	pr_out("            system set netns { shared | exclusive }\n");
+	return 0;
+}
+
+static int sys_set(struct rd *rd)
+{
+	const struct rd_cmd cmds[] = {
+		{ NULL,			sys_set_help },
+		{ "help",		sys_set_help },
+		{ "netns",		sys_set_netns_args},
+		{ 0 }
+	};
+
+	return rd_exec_cmd(rd, cmds, "parameter");
+}
+
+int cmd_sys(struct rd *rd)
+{
+	const struct rd_cmd cmds[] = {
+		{ NULL,		sys_show },
+		{ "show",	sys_show },
+		{ "set",	sys_set },
+		{ "help",	sys_help },
+		{ 0 }
+	};
+
+	return rd_exec_cmd(rd, cmds, "system command");
+}

rdma/utils.c

@@ -435,6 +435,7 @@ static const enum mnl_attr_data_type nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_DRIVER_U32] = MNL_TYPE_U32,
 	[RDMA_NLDEV_ATTR_DRIVER_S64] = MNL_TYPE_U64,
 	[RDMA_NLDEV_ATTR_DRIVER_U64] = MNL_TYPE_U64,
+	[RDMA_NLDEV_SYS_ATTR_NETNS_MODE] = MNL_TYPE_U8,
 };
 
 int rd_attr_check(const struct nlattr *attr, int *typep)