Merge branch 'devlink-use-spec-to-generate-split-ops'

Jiri Pirko says:

====================
devlink: use spec to generate split ops

This is an outcome of the discussion in the following thread:
https://lore.kernel.org/netdev/[e-mail]/
It serves as a dependency on the linked selector patchset.

There is an existing spec for devlink used for userspace part
generation. There are two commands supported there.

This patchset extends the spec so kernel split ops code could
be generated from it.
====================

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/netlink/genetlink-c.yaml

···
               description: Kernel attribute validation flags.
               type: array
               items:
-                enum: [ strict, dump ]
+                enum: [ strict, dump, dump-strict ]
             do: &subop-type
               description: Main command handler.
               type: object

Documentation/netlink/genetlink-legacy.yaml

···
               description: Kernel attribute validation flags.
               type: array
               items:
-                enum: [ strict, dump ]
+                enum: [ strict, dump, dump-strict ]
             # Start genetlink-legacy
             fixed-header: *fixed-header
             # End genetlink-legacy

Documentation/netlink/genetlink.yaml

···
               description: Kernel attribute validation flags.
               type: array
               items:
-                enum: [ strict, dump ]
+                enum: [ strict, dump, dump-strict ]
             do: &subop-type
               description: Main command handler.
               type: object

Documentation/netlink/specs/devlink.yaml

···
       name: get
       doc: Get devlink instances.
       attribute-set: devlink
+      dont-validate:
+        - strict
+        - dump
 
       do:
+        pre: devlink-nl-pre-doit
+        post: devlink-nl-post-doit
         request:
           value: 1
           attributes: &dev-id-attrs
···
       name: info-get
       doc: Get device information, like driver name, hardware and firmware versions etc.
       attribute-set: devlink
+      dont-validate:
+        - strict
+        - dump
 
       do:
+        pre: devlink-nl-pre-doit
+        post: devlink-nl-post-doit
         request:
           value: 51
           attributes: *dev-id-attrs
-        reply:
+        reply: &info-get-reply
           value: 51
           attributes:
             - bus-name
···
             - info-version-fixed
             - info-version-running
             - info-version-stored
+      dump:
+        reply: *info-get-reply

net/devlink/Makefile

···
 # SPDX-License-Identifier: GPL-2.0
 
-obj-y := leftover.o core.o netlink.o dev.o health.o
+obj-y := leftover.o core.o netlink.o netlink_gen.o dev.o health.o

net/devlink/dev.c

···
 				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
 }
 
-int devlink_nl_cmd_get_doit(struct sk_buff *skb, struct genl_info *info)
+int devlink_nl_get_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct devlink *devlink = info->user_ptr[0];
 	struct sk_buff *msg;
···
 }
 
 static int
-devlink_nl_cmd_get_dump_one(struct sk_buff *msg, struct devlink *devlink,
-			    struct netlink_callback *cb)
+devlink_nl_get_dump_one(struct sk_buff *msg, struct devlink *devlink,
+			struct netlink_callback *cb)
 {
 	return devlink_nl_fill(msg, devlink, DEVLINK_CMD_NEW,
 			       NETLINK_CB(cb->skb).portid,
 			       cb->nlh->nlmsg_seq, NLM_F_MULTI);
 }
 
-const struct devlink_cmd devl_cmd_get = {
-	.dump_one		= devlink_nl_cmd_get_dump_one,
-};
+int devlink_nl_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	return devlink_nl_dumpit(msg, cb, devlink_nl_get_dump_one);
+}
 
 static void devlink_reload_failed_set(struct devlink *devlink,
 				      bool reload_failed)
···
 	return err;
 }
 
-int devlink_nl_cmd_info_get_doit(struct sk_buff *skb, struct genl_info *info)
+int devlink_nl_info_get_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct devlink *devlink = info->user_ptr[0];
 	struct sk_buff *msg;
···
 }
 
 static int
-devlink_nl_cmd_info_get_dump_one(struct sk_buff *msg, struct devlink *devlink,
-				 struct netlink_callback *cb)
+devlink_nl_info_get_dump_one(struct sk_buff *msg, struct devlink *devlink,
+			     struct netlink_callback *cb)
 {
 	int err;
 
···
 	return err;
 }
 
-const struct devlink_cmd devl_cmd_info_get = {
-	.dump_one		= devlink_nl_cmd_info_get_dump_one,
-};
+int devlink_nl_info_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	return devlink_nl_dumpit(msg, cb, devlink_nl_info_get_dump_one);
+}
 
 static int devlink_nl_flash_update_fill(struct sk_buff *msg,
 					struct devlink *devlink,

net/devlink/devl_internal.h

···
 #include <net/devlink.h>
 #include <net/net_namespace.h>
 
+#include "netlink_gen.h"
+
 #define DEVLINK_REGISTERED XA_MARK_1
 
 #define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
···
 	};
 };
 
+typedef int devlink_nl_dump_one_func_t(struct sk_buff *msg,
+				       struct devlink *devlink,
+				       struct netlink_callback *cb);
+
 struct devlink_cmd {
-	int (*dump_one)(struct sk_buff *msg, struct devlink *devlink,
-			struct netlink_callback *cb);
+	devlink_nl_dump_one_func_t *dump_one;
 };
 
-extern const struct genl_small_ops devlink_nl_ops[56];
+extern const struct genl_small_ops devlink_nl_small_ops[54];
 
 struct devlink *
 devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs);
···
 void devlink_notify_unregister(struct devlink *devlink);
 void devlink_notify_register(struct devlink *devlink);
 
-int devlink_nl_instance_iter_dumpit(struct sk_buff *msg,
-				    struct netlink_callback *cb);
+int devlink_nl_dumpit(struct sk_buff *msg, struct netlink_callback *cb,
+		      devlink_nl_dump_one_func_t *dump_one);
+int devlink_nl_instance_iter_dumpit(struct sk_buff *msg, struct netlink_callback *cb);
 
 static inline struct devlink_nl_dump_state *
 devlink_dump_state(struct netlink_callback *cb)
···
 }
 
 /* Commands */
-extern const struct devlink_cmd devl_cmd_get;
 extern const struct devlink_cmd devl_cmd_port_get;
 extern const struct devlink_cmd devl_cmd_sb_get;
 extern const struct devlink_cmd devl_cmd_sb_pool_get;
···
 extern const struct devlink_cmd devl_cmd_sb_tc_pool_bind_get;
 extern const struct devlink_cmd devl_cmd_param_get;
 extern const struct devlink_cmd devl_cmd_region_get;
-extern const struct devlink_cmd devl_cmd_info_get;
 extern const struct devlink_cmd devl_cmd_health_reporter_get;
 extern const struct devlink_cmd devl_cmd_trap_get;
 extern const struct devlink_cmd devl_cmd_trap_group_get;
···
 devlink_rate_node_get_from_info(struct devlink *devlink,
 				struct genl_info *info);
 /* Devlink nl cmds */
-int devlink_nl_cmd_get_doit(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_eswitch_get_doit(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_eswitch_set_doit(struct sk_buff *skb, struct genl_info *info);
-int devlink_nl_cmd_info_get_doit(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_flash_update(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_selftests_get_doit(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_cmd_selftests_run(struct sk_buff *skb, struct genl_info *info);

net/devlink/leftover.c

···
 	return devlink_trap_policer_set(devlink, policer_item, info);
 }
 
-const struct genl_small_ops devlink_nl_ops[56] = {
-	{
-		.cmd = DEVLINK_CMD_GET,
-		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
-		.doit = devlink_nl_cmd_get_doit,
-		.dumpit = devlink_nl_instance_iter_dumpit,
-		/* can be retrieved by unprivileged users */
-	},
+const struct genl_small_ops devlink_nl_small_ops[54] = {
 	{
 		.cmd = DEVLINK_CMD_PORT_GET,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
···
 			    GENL_DONT_VALIDATE_DUMP_STRICT,
 		.dumpit = devlink_nl_cmd_region_read_dumpit,
 		.flags = GENL_ADMIN_PERM,
-	},
-	{
-		.cmd = DEVLINK_CMD_INFO_GET,
-		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
-		.doit = devlink_nl_cmd_info_get_doit,
-		.dumpit = devlink_nl_instance_iter_dumpit,
-		/* can be retrieved by unprivileged users */
 	},
 	{
 		.cmd = DEVLINK_CMD_HEALTH_REPORTER_GET,

net/devlink/netlink.c

···
 	return ERR_PTR(-ENODEV);
 }
 
-static int devlink_nl_pre_doit(const struct genl_split_ops *ops,
-			       struct sk_buff *skb, struct genl_info *info)
+int devlink_nl_pre_doit(const struct genl_split_ops *ops,
+			struct sk_buff *skb, struct genl_info *info)
 {
 	struct devlink_linecard *linecard;
 	struct devlink_port *devlink_port;
···
 	return err;
 }
 
-static void devlink_nl_post_doit(const struct genl_split_ops *ops,
-				 struct sk_buff *skb, struct genl_info *info)
+void devlink_nl_post_doit(const struct genl_split_ops *ops,
+			  struct sk_buff *skb, struct genl_info *info)
 {
 	struct devlink *devlink;
 
···
 }
 
 static const struct devlink_cmd *devl_cmds[] = {
-	[DEVLINK_CMD_GET]		= &devl_cmd_get,
 	[DEVLINK_CMD_PORT_GET]		= &devl_cmd_port_get,
 	[DEVLINK_CMD_SB_GET]		= &devl_cmd_sb_get,
 	[DEVLINK_CMD_SB_POOL_GET]	= &devl_cmd_sb_pool_get,
···
 	[DEVLINK_CMD_SB_TC_POOL_BIND_GET] = &devl_cmd_sb_tc_pool_bind_get,
 	[DEVLINK_CMD_PARAM_GET]		= &devl_cmd_param_get,
 	[DEVLINK_CMD_REGION_GET]	= &devl_cmd_region_get,
-	[DEVLINK_CMD_INFO_GET]		= &devl_cmd_info_get,
 	[DEVLINK_CMD_HEALTH_REPORTER_GET] = &devl_cmd_health_reporter_get,
 	[DEVLINK_CMD_TRAP_GET]		= &devl_cmd_trap_get,
 	[DEVLINK_CMD_TRAP_GROUP_GET]	= &devl_cmd_trap_group_get,
···
 	[DEVLINK_CMD_SELFTESTS_GET]	= &devl_cmd_selftests_get,
 };
 
-int devlink_nl_instance_iter_dumpit(struct sk_buff *msg,
-				    struct netlink_callback *cb)
+int devlink_nl_dumpit(struct sk_buff *msg, struct netlink_callback *cb,
+		      devlink_nl_dump_one_func_t *dump_one)
 {
-	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 	struct devlink_nl_dump_state *state = devlink_dump_state(cb);
-	const struct devlink_cmd *cmd;
 	struct devlink *devlink;
 	int err = 0;
-
-	cmd = devl_cmds[info->op.cmd];
 
 	while ((devlink = devlinks_xa_find_get(sock_net(msg->sk),
 					       &state->instance))) {
 		devl_lock(devlink);
 
 		if (devl_is_registered(devlink))
-			err = cmd->dump_one(msg, devlink, cb);
+			err = dump_one(msg, devlink, cb);
 		else
 			err = 0;
 
···
 	return msg->len;
 }
 
+int devlink_nl_instance_iter_dumpit(struct sk_buff *msg,
+				    struct netlink_callback *cb)
+{
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	const struct devlink_cmd *cmd = devl_cmds[info->op.cmd];
+
+	return devlink_nl_dumpit(msg, cb, cmd->dump_one);
+}
+
 struct genl_family devlink_nl_family __ro_after_init = {
 	.name		= DEVLINK_GENL_NAME,
 	.version	= DEVLINK_GENL_VERSION,
···
 	.pre_doit	= devlink_nl_pre_doit,
 	.post_doit	= devlink_nl_post_doit,
 	.module		= THIS_MODULE,
-	.small_ops	= devlink_nl_ops,
-	.n_small_ops	= ARRAY_SIZE(devlink_nl_ops),
+	.small_ops	= devlink_nl_small_ops,
+	.n_small_ops	= ARRAY_SIZE(devlink_nl_small_ops),
+	.split_ops	= devlink_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(devlink_nl_ops),
 	.resv_start_op	= DEVLINK_CMD_SELFTESTS_RUN + 1,
 	.mcgrps		= devlink_nl_mcgrps,
 	.n_mcgrps	= ARRAY_SIZE(devlink_nl_mcgrps),

net/devlink/netlink_gen.c

···
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/devlink.yaml */
+/* YNL-GEN kernel source */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "netlink_gen.h"
+
+#include <uapi/linux/devlink.h>
+
+/* DEVLINK_CMD_GET - do */
+static const struct nla_policy devlink_get_nl_policy[DEVLINK_ATTR_DEV_NAME + 1] = {
+	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
+};
+
+/* DEVLINK_CMD_INFO_GET - do */
+static const struct nla_policy devlink_info_get_nl_policy[DEVLINK_ATTR_DEV_NAME + 1] = {
+	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
+	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
+};
+
+/* Ops table for devlink */
+const struct genl_split_ops devlink_nl_ops[4] = {
+	{
+		.cmd		= DEVLINK_CMD_GET,
+		.validate	= GENL_DONT_VALIDATE_STRICT,
+		.pre_doit	= devlink_nl_pre_doit,
+		.doit		= devlink_nl_get_doit,
+		.post_doit	= devlink_nl_post_doit,
+		.policy		= devlink_get_nl_policy,
+		.maxattr	= DEVLINK_ATTR_DEV_NAME,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DEVLINK_CMD_GET,
+		.validate	= GENL_DONT_VALIDATE_DUMP,
+		.dumpit		= devlink_nl_get_dumpit,
+		.flags		= GENL_CMD_CAP_DUMP,
+	},
+	{
+		.cmd		= DEVLINK_CMD_INFO_GET,
+		.validate	= GENL_DONT_VALIDATE_STRICT,
+		.pre_doit	= devlink_nl_pre_doit,
+		.doit		= devlink_nl_info_get_doit,
+		.post_doit	= devlink_nl_post_doit,
+		.policy		= devlink_info_get_nl_policy,
+		.maxattr	= DEVLINK_ATTR_DEV_NAME,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= DEVLINK_CMD_INFO_GET,
+		.validate	= GENL_DONT_VALIDATE_DUMP,
+		.dumpit		= devlink_nl_info_get_dumpit,
+		.flags		= GENL_CMD_CAP_DUMP,
+	},
+};

net/devlink/netlink_gen.h

···
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/devlink.yaml */
+/* YNL-GEN kernel header */
+
+#ifndef _LINUX_DEVLINK_GEN_H
+#define _LINUX_DEVLINK_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/devlink.h>
+
+/* Ops table for devlink */
+extern const struct genl_split_ops devlink_nl_ops[4];
+
+int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+			struct genl_info *info);
+void
+devlink_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+		     struct genl_info *info);
+
+int devlink_nl_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int devlink_nl_info_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_info_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+
+#endif /* _LINUX_DEVLINK_GEN_H */

tools/net/ynl/generated/devlink-user.c

···
 	return NULL;
 }
 
+/* DEVLINK_CMD_INFO_GET - dump */
+void devlink_info_get_list_free(struct devlink_info_get_list *rsp)
+{
+	struct devlink_info_get_list *next = rsp;
+
+	while ((void *)next != YNL_LIST_END) {
+		unsigned int i;
+
+		rsp = next;
+		next = rsp->next;
+
+		free(rsp->obj.bus_name);
+		free(rsp->obj.dev_name);
+		free(rsp->obj.info_driver_name);
+		free(rsp->obj.info_serial_number);
+		for (i = 0; i < rsp->obj.n_info_version_fixed; i++)
+			devlink_dl_info_version_free(&rsp->obj.info_version_fixed[i]);
+		free(rsp->obj.info_version_fixed);
+		for (i = 0; i < rsp->obj.n_info_version_running; i++)
+			devlink_dl_info_version_free(&rsp->obj.info_version_running[i]);
+		free(rsp->obj.info_version_running);
+		for (i = 0; i < rsp->obj.n_info_version_stored; i++)
+			devlink_dl_info_version_free(&rsp->obj.info_version_stored[i]);
+		free(rsp->obj.info_version_stored);
+		free(rsp);
+	}
+}
+
+struct devlink_info_get_list *devlink_info_get_dump(struct ynl_sock *ys)
+{
+	struct ynl_dump_state yds = {};
+	struct nlmsghdr *nlh;
+	int err;
+
+	yds.ys = ys;
+	yds.alloc_sz = sizeof(struct devlink_info_get_list);
+	yds.cb = devlink_info_get_rsp_parse;
+	yds.rsp_cmd = DEVLINK_CMD_INFO_GET;
+	yds.rsp_policy = &devlink_nest;
+
+	nlh = ynl_gemsg_start_dump(ys, ys->family_id, DEVLINK_CMD_INFO_GET, 1);
+
+	err = ynl_exec_dump(ys, nlh, &yds);
+	if (err < 0)
+		goto free_list;
+
+	return yds.first;
+
+free_list:
+	devlink_info_get_list_free(yds.first);
+	return NULL;
+}
+
 const struct ynl_family ynl_devlink_family =  {
 	.name		= "devlink",
 };

tools/net/ynl/generated/devlink-user.h

···
 struct devlink_info_get_rsp *
 devlink_info_get(struct ynl_sock *ys, struct devlink_info_get_req *req);
 
+/* DEVLINK_CMD_INFO_GET - dump */
+struct devlink_info_get_list {
+	struct devlink_info_get_list *next;
+	struct devlink_info_get_rsp obj __attribute__ ((aligned (8)));
+};
+
+void devlink_info_get_list_free(struct devlink_info_get_list *rsp);
+
+struct devlink_info_get_list *devlink_info_get_dump(struct ynl_sock *ys);
+
 #endif /* _LINUX_DEVLINK_GEN_H */

tools/net/ynl/ynl-gen-c.py

···
 
 
 def print_req_policy_fwd(cw, struct, ri=None, terminate=True):
-    if terminate and ri and kernel_can_gen_family_struct(struct.family):
+    if terminate and ri and policy_should_be_static(struct.family):
         return
 
     if terminate:
         prefix = 'extern '
     else:
-        if kernel_can_gen_family_struct(struct.family) and ri:
+        if ri and policy_should_be_static(struct.family):
             prefix = 'static '
         else:
             prefix = ''
···
 
 def kernel_can_gen_family_struct(family):
     return family.proto == 'genetlink'
+
+
+def policy_should_be_static(family):
+    return family.kernel_policy == 'split' or kernel_can_gen_family_struct(family)
 
 
 def print_kernel_op_table_fwd(family, cw, terminate):
···
                 cw.block_start()
                 members = [('cmd', op.enum_name)]
                 if 'dont-validate' in op:
+                    dont_validate = []
+                    for x in op['dont-validate']:
+                        if op_mode == 'do' and x in ['dump', 'dump-strict']:
+                            continue
+                        if op_mode == "dump" and x == 'strict':
+                            continue
+                        dont_validate.append(x)
+
                     members.append(('validate',
                                     ' | '.join([c_upper('genl-dont-validate-' + x)
-                                                for x in op['dont-validate']])), )
+                                                for x in dont_validate])), )
                 name = c_lower(f"{family.name}-nl-{op_name}-{op_mode}it")
                 if 'pre' in op[op_mode]:
                     members.append((cb_names[op_mode]['pre'], c_lower(op[op_mode]['pre'])))
···
         return
 
     supported_models = ['unified']
-    if args.mode == 'user':
+    if args.mode in ['user', 'kernel']:
         supported_models += ['directional']
     if parsed.msg_id_model not in supported_models:
         print(f'Message enum-model {parsed.msg_id_model} not supported for {args.mode} generation')