Merge branch 'devlink-code-split-and-structured-instance-walk'

Jakub Kicinski says:

====================
devlink: code split and structured instance walk

Split devlink.c into a handful of files, trying to keep the "core"
code away from all the command-specific implementations.
The core code has been quite scattered until now. Going forward we can
consider using a source file per-subobject, I think that it's quite
beneficial to newcomers (based on relative ease with which folks
contribute to ethtool vs devlink). But this series doesn't split
everything out, yet - partially due to backporting concerns,
but mostly due to lack of time. Bulk of the netlink command
handling is left in a leftover.c file.

Introduce a context structure for dumps, and use it to store
the devlink instance ID of the last dumped devlink instance.
This means we don't have to restart the walk from 0 each time.

Finally - introduce a "structured walk". A centralized dump handler
in devlink/netlink.c which walks the devlink instances, deals with
refcounting/locking, simplifying the per-object implementations quite
a bit. Inspired by the ethtool code.

v1: https://lore.kernel.org/all/20230104041636.226398-1-kuba@kernel.org/
RFC: https://lore.kernel.org/all/20221215020155.1619839-1-kuba@kernel.org/
====================

Link: https://lore.kernel.org/r/20230105040531.353563-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 207 insertions, 0 deletions

diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
new file mode 100644
index 000000000000..adf9f6c177db
--- /dev/null
+++ b/net/devlink/devl_internal.h
@@ -0,0 +1,207 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (c) 2016 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016 Jiri Pirko <jiri@mellanox.com>
+ */
+
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/types.h>
+#include <linux/xarray.h>
+#include <net/devlink.h>
+#include <net/net_namespace.h>
+
+#define DEVLINK_REGISTERED XA_MARK_1
+#define DEVLINK_UNREGISTERING XA_MARK_2
+
+#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
+	(__DEVLINK_RELOAD_LIMIT_MAX * __DEVLINK_RELOAD_ACTION_MAX)
+
+struct devlink_dev_stats {
+	u32 reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+	u32 remote_reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+};
+
+struct devlink {
+	u32 index;
+	struct xarray ports;
+	struct list_head rate_list;
+	struct list_head sb_list;
+	struct list_head dpipe_table_list;
+	struct list_head resource_list;
+	struct list_head param_list;
+	struct list_head region_list;
+	struct list_head reporter_list;
+	struct mutex reporters_lock; /* protects reporter_list */
+	struct devlink_dpipe_headers *dpipe_headers;
+	struct list_head trap_list;
+	struct list_head trap_group_list;
+	struct list_head trap_policer_list;
+	struct list_head linecard_list;
+	struct mutex linecards_lock; /* protects linecard_list */
+	const struct devlink_ops *ops;
+	u64 features;
+	struct xarray snapshot_ids;
+	struct devlink_dev_stats stats;
+	struct device *dev;
+	possible_net_t _net;
+	/* Serializes access to devlink instance specific objects such as
+	 * port, sb, dpipe, resource, params, region, traps and more.
+	 */
+	struct mutex lock;
+	struct lock_class_key lock_key;
+	u8 reload_failed:1;
+	refcount_t refcount;
+	struct completion comp;
+	struct rcu_head rcu;
+	struct notifier_block netdevice_nb;
+	char priv[] __aligned(NETDEV_ALIGN);
+};
+
+extern struct xarray devlinks;
+extern struct genl_family devlink_nl_family;
+
+/* devlink instances are open to the access from the user space after
+ * devlink_register() call. Such logical barrier allows us to have certain
+ * expectations related to locking.
+ *
+ * Before *_register() - we are in initialization stage and no parallel
+ * access possible to the devlink instance. All drivers perform that phase
+ * by implicitly holding device_lock.
+ *
+ * After *_register() - users and driver can access devlink instance at
+ * the same time.
+ */
+#define ASSERT_DEVLINK_REGISTERED(d)                                           \
+	WARN_ON_ONCE(!xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
+#define ASSERT_DEVLINK_NOT_REGISTERED(d)                                       \
+	WARN_ON_ONCE(xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
+
+/* Iterate over devlink pointers which were possible to get reference to.
+ * devlink_put() needs to be called for each iterated devlink pointer
+ * in loop body in order to release the reference.
+ */
+#define devlinks_xa_for_each_registered_get(net, index, devlink)	\
+	for (index = 0,							\
+	     devlink = devlinks_xa_find_get_first(net, &index);	\
+	     devlink; devlink = devlinks_xa_find_get_next(net, &index))
+
+struct devlink *
+devlinks_xa_find_get(struct net *net, unsigned long *indexp,
+		     void * (*xa_find_fn)(struct xarray *, unsigned long *,
+					  unsigned long, xa_mark_t));
+struct devlink *
+devlinks_xa_find_get_first(struct net *net, unsigned long *indexp);
+struct devlink *
+devlinks_xa_find_get_next(struct net *net, unsigned long *indexp);
+
+/* Netlink */
+#define DEVLINK_NL_FLAG_NEED_PORT		BIT(0)
+#define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT	BIT(1)
+#define DEVLINK_NL_FLAG_NEED_RATE		BIT(2)
+#define DEVLINK_NL_FLAG_NEED_RATE_NODE		BIT(3)
+#define DEVLINK_NL_FLAG_NEED_LINECARD		BIT(4)
+
+enum devlink_multicast_groups {
+	DEVLINK_MCGRP_CONFIG,
+};
+
+/* state held across netlink dumps */
+struct devlink_nl_dump_state {
+	unsigned long instance;
+	int idx;
+	union {
+		/* DEVLINK_CMD_REGION_READ */
+		struct {
+			u64 start_offset;
+		};
+		/* DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET */
+		struct {
+			u64 dump_ts;
+		};
+	};
+};
+
+struct devlink_gen_cmd {
+	int (*dump_one)(struct sk_buff *msg, struct devlink *devlink,
+			struct netlink_callback *cb);
+};
+
+/* Iterate over registered devlink instances for devlink dump.
+ * devlink_put() needs to be called for each iterated devlink pointer
+ * in loop body in order to release the reference.
+ * Note: this is NOT a generic iterator, it makes assumptions about the use
+ *	 of @state and can only be used once per dumpit implementation.
+ */
+#define devlink_dump_for_each_instance_get(msg, state, devlink)		\
+	for (; (devlink = devlinks_xa_find_get(sock_net(msg->sk),	\
+					       &state->instance, xa_find)); \
+	     state->instance++, state->idx = 0)
+
+extern const struct genl_small_ops devlink_nl_ops[56];
+
+struct devlink *devlink_get_from_attrs(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_dump(struct sk_buff *msg,
+				  struct netlink_callback *cb);
+
+static inline struct devlink_nl_dump_state *
+devlink_dump_state(struct netlink_callback *cb)
+{
+	NL_ASSET_DUMP_CTX_FITS(struct devlink_nl_dump_state);
+
+	return (struct devlink_nl_dump_state *)cb->ctx;
+}
+
+/* gen cmds */
+extern const struct devlink_gen_cmd devl_gen_inst;
+extern const struct devlink_gen_cmd devl_gen_port;
+extern const struct devlink_gen_cmd devl_gen_sb;
+extern const struct devlink_gen_cmd devl_gen_sb_pool;
+extern const struct devlink_gen_cmd devl_gen_sb_port_pool;
+extern const struct devlink_gen_cmd devl_gen_sb_tc_pool_bind;
+extern const struct devlink_gen_cmd devl_gen_selftests;
+extern const struct devlink_gen_cmd devl_gen_param;
+extern const struct devlink_gen_cmd devl_gen_region;
+extern const struct devlink_gen_cmd devl_gen_info;
+extern const struct devlink_gen_cmd devl_gen_trap;
+extern const struct devlink_gen_cmd devl_gen_trap_group;
+extern const struct devlink_gen_cmd devl_gen_trap_policer;
+
+/* Ports */
+int devlink_port_netdevice_event(struct notifier_block *nb,
+				 unsigned long event, void *ptr);
+
+struct devlink_port *
+devlink_port_get_from_info(struct devlink *devlink, struct genl_info *info);
+
+/* Reload */
+bool devlink_reload_actions_valid(const struct devlink_ops *ops);
+int devlink_reload(struct devlink *devlink, struct net *dest_net,
+		   enum devlink_reload_action action,
+		   enum devlink_reload_limit limit,
+		   u32 *actions_performed, struct netlink_ext_ack *extack);
+
+static inline bool devlink_reload_supported(const struct devlink_ops *ops)
+{
+	return ops->reload_down && ops->reload_up;
+}
+
+/* Line cards */
+struct devlink_linecard;
+
+struct devlink_linecard *
+devlink_linecard_get_from_info(struct devlink *devlink, struct genl_info *info);
+void devlink_linecard_put(struct devlink_linecard *linecard);
+
+/* Rates */
+extern const struct devlink_gen_cmd devl_gen_rate_get;
+
+struct devlink_rate *
+devlink_rate_get_from_info(struct devlink *devlink, struct genl_info *info);
+struct devlink_rate *
+devlink_rate_node_get_from_info(struct devlink *devlink,
+				struct genl_info *info);