Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1260 insertions, 0 deletions

diff --git a/net/devlink/region.c b/net/devlink/region.c
new file mode 100644
index 0000000000..d197cdb662
--- /dev/null
+++ b/net/devlink/region.c
@@ -0,0 +1,1260 @@
+// 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 "devl_internal.h"
+
+struct devlink_region {
+	struct devlink *devlink;
+	struct devlink_port *port;
+	struct list_head list;
+	union {
+		const struct devlink_region_ops *ops;
+		const struct devlink_port_region_ops *port_ops;
+	};
+	struct mutex snapshot_lock; /* protects snapshot_list,
+				     * max_snapshots and cur_snapshots
+				     * consistency.
+				     */
+	struct list_head snapshot_list;
+	u32 max_snapshots;
+	u32 cur_snapshots;
+	u64 size;
+};
+
+struct devlink_snapshot {
+	struct list_head list;
+	struct devlink_region *region;
+	u8 *data;
+	u32 id;
+};
+
+static struct devlink_region *
+devlink_region_get_by_name(struct devlink *devlink, const char *region_name)
+{
+	struct devlink_region *region;
+
+	list_for_each_entry(region, &devlink->region_list, list)
+		if (!strcmp(region->ops->name, region_name))
+			return region;
+
+	return NULL;
+}
+
+static struct devlink_region *
+devlink_port_region_get_by_name(struct devlink_port *port,
+				const char *region_name)
+{
+	struct devlink_region *region;
+
+	list_for_each_entry(region, &port->region_list, list)
+		if (!strcmp(region->ops->name, region_name))
+			return region;
+
+	return NULL;
+}
+
+static struct devlink_snapshot *
+devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
+{
+	struct devlink_snapshot *snapshot;
+
+	list_for_each_entry(snapshot, &region->snapshot_list, list)
+		if (snapshot->id == id)
+			return snapshot;
+
+	return NULL;
+}
+
+static int devlink_nl_region_snapshot_id_put(struct sk_buff *msg,
+					     struct devlink *devlink,
+					     struct devlink_snapshot *snapshot)
+{
+	struct nlattr *snap_attr;
+	int err;
+
+	snap_attr = nla_nest_start_noflag(msg, DEVLINK_ATTR_REGION_SNAPSHOT);
+	if (!snap_attr)
+		return -EINVAL;
+
+	err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID, snapshot->id);
+	if (err)
+		goto nla_put_failure;
+
+	nla_nest_end(msg, snap_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, snap_attr);
+	return err;
+}
+
+static int devlink_nl_region_snapshots_id_put(struct sk_buff *msg,
+					      struct devlink *devlink,
+					      struct devlink_region *region)
+{
+	struct devlink_snapshot *snapshot;
+	struct nlattr *snapshots_attr;
+	int err;
+
+	snapshots_attr = nla_nest_start_noflag(msg,
+					       DEVLINK_ATTR_REGION_SNAPSHOTS);
+	if (!snapshots_attr)
+		return -EINVAL;
+
+	list_for_each_entry(snapshot, &region->snapshot_list, list) {
+		err = devlink_nl_region_snapshot_id_put(msg, devlink, snapshot);
+		if (err)
+			goto nla_put_failure;
+	}
+
+	nla_nest_end(msg, snapshots_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, snapshots_attr);
+	return err;
+}
+
+static int devlink_nl_region_fill(struct sk_buff *msg, struct devlink *devlink,
+				  enum devlink_command cmd, u32 portid,
+				  u32 seq, int flags,
+				  struct devlink_region *region)
+{
+	void *hdr;
+	int err;
+
+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	err = devlink_nl_put_handle(msg, devlink);
+	if (err)
+		goto nla_put_failure;
+
+	if (region->port) {
+		err = nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX,
+				  region->port->index);
+		if (err)
+			goto nla_put_failure;
+	}
+
+	err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME, region->ops->name);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_SIZE,
+				region->size,
+				DEVLINK_ATTR_PAD);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_u32(msg, DEVLINK_ATTR_REGION_MAX_SNAPSHOTS,
+			  region->max_snapshots);
+	if (err)
+		goto nla_put_failure;
+
+	err = devlink_nl_region_snapshots_id_put(msg, devlink, region);
+	if (err)
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return err;
+}
+
+static struct sk_buff *
+devlink_nl_region_notify_build(struct devlink_region *region,
+			       struct devlink_snapshot *snapshot,
+			       enum devlink_command cmd, u32 portid, u32 seq)
+{
+	struct devlink *devlink = region->devlink;
+	struct sk_buff *msg;
+	void *hdr;
+	int err;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return ERR_PTR(-ENOMEM);
+
+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, 0, cmd);
+	if (!hdr) {
+		err = -EMSGSIZE;
+		goto out_free_msg;
+	}
+
+	err = devlink_nl_put_handle(msg, devlink);
+	if (err)
+		goto out_cancel_msg;
+
+	if (region->port) {
+		err = nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX,
+				  region->port->index);
+		if (err)
+			goto out_cancel_msg;
+	}
+
+	err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME,
+			     region->ops->name);
+	if (err)
+		goto out_cancel_msg;
+
+	if (snapshot) {
+		err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID,
+				  snapshot->id);
+		if (err)
+			goto out_cancel_msg;
+	} else {
+		err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_SIZE,
+					region->size, DEVLINK_ATTR_PAD);
+		if (err)
+			goto out_cancel_msg;
+	}
+	genlmsg_end(msg, hdr);
+
+	return msg;
+
+out_cancel_msg:
+	genlmsg_cancel(msg, hdr);
+out_free_msg:
+	nlmsg_free(msg);
+	return ERR_PTR(err);
+}
+
+static void devlink_nl_region_notify(struct devlink_region *region,
+				     struct devlink_snapshot *snapshot,
+				     enum devlink_command cmd)
+{
+	struct devlink *devlink = region->devlink;
+	struct sk_buff *msg;
+
+	WARN_ON(cmd != DEVLINK_CMD_REGION_NEW && cmd != DEVLINK_CMD_REGION_DEL);
+	if (!xa_get_mark(&devlinks, devlink->index, DEVLINK_REGISTERED))
+		return;
+
+	msg = devlink_nl_region_notify_build(region, snapshot, cmd, 0, 0);
+	if (IS_ERR(msg))
+		return;
+
+	genlmsg_multicast_netns(&devlink_nl_family, devlink_net(devlink), msg,
+				0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
+}
+
+void devlink_regions_notify_register(struct devlink *devlink)
+{
+	struct devlink_region *region;
+
+	list_for_each_entry(region, &devlink->region_list, list)
+		devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);
+}
+
+void devlink_regions_notify_unregister(struct devlink *devlink)
+{
+	struct devlink_region *region;
+
+	list_for_each_entry_reverse(region, &devlink->region_list, list)
+		devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_DEL);
+}
+
+/**
+ * __devlink_snapshot_id_increment - Increment number of snapshots using an id
+ *	@devlink: devlink instance
+ *	@id: the snapshot id
+ *
+ *	Track when a new snapshot begins using an id. Load the count for the
+ *	given id from the snapshot xarray, increment it, and store it back.
+ *
+ *	Called when a new snapshot is created with the given id.
+ *
+ *	The id *must* have been previously allocated by
+ *	devlink_region_snapshot_id_get().
+ *
+ *	Returns 0 on success, or an error on failure.
+ */
+static int __devlink_snapshot_id_increment(struct devlink *devlink, u32 id)
+{
+	unsigned long count;
+	void *p;
+	int err;
+
+	xa_lock(&devlink->snapshot_ids);
+	p = xa_load(&devlink->snapshot_ids, id);
+	if (WARN_ON(!p)) {
+		err = -EINVAL;
+		goto unlock;
+	}
+
+	if (WARN_ON(!xa_is_value(p))) {
+		err = -EINVAL;
+		goto unlock;
+	}
+
+	count = xa_to_value(p);
+	count++;
+
+	err = xa_err(__xa_store(&devlink->snapshot_ids, id, xa_mk_value(count),
+				GFP_ATOMIC));
+unlock:
+	xa_unlock(&devlink->snapshot_ids);
+	return err;
+}
+
+/**
+ * __devlink_snapshot_id_decrement - Decrease number of snapshots using an id
+ *	@devlink: devlink instance
+ *	@id: the snapshot id
+ *
+ *	Track when a snapshot is deleted and stops using an id. Load the count
+ *	for the given id from the snapshot xarray, decrement it, and store it
+ *	back.
+ *
+ *	If the count reaches zero, erase this id from the xarray, freeing it
+ *	up for future re-use by devlink_region_snapshot_id_get().
+ *
+ *	Called when a snapshot using the given id is deleted, and when the
+ *	initial allocator of the id is finished using it.
+ */
+static void __devlink_snapshot_id_decrement(struct devlink *devlink, u32 id)
+{
+	unsigned long count;
+	void *p;
+
+	xa_lock(&devlink->snapshot_ids);
+	p = xa_load(&devlink->snapshot_ids, id);
+	if (WARN_ON(!p))
+		goto unlock;
+
+	if (WARN_ON(!xa_is_value(p)))
+		goto unlock;
+
+	count = xa_to_value(p);
+
+	if (count > 1) {
+		count--;
+		__xa_store(&devlink->snapshot_ids, id, xa_mk_value(count),
+			   GFP_ATOMIC);
+	} else {
+		/* If this was the last user, we can erase this id */
+		__xa_erase(&devlink->snapshot_ids, id);
+	}
+unlock:
+	xa_unlock(&devlink->snapshot_ids);
+}
+
+/**
+ *	__devlink_snapshot_id_insert - Insert a specific snapshot ID
+ *	@devlink: devlink instance
+ *	@id: the snapshot id
+ *
+ *	Mark the given snapshot id as used by inserting a zero value into the
+ *	snapshot xarray.
+ *
+ *	This must be called while holding the devlink instance lock. Unlike
+ *	devlink_snapshot_id_get, the initial reference count is zero, not one.
+ *	It is expected that the id will immediately be used before
+ *	releasing the devlink instance lock.
+ *
+ *	Returns zero on success, or an error code if the snapshot id could not
+ *	be inserted.
+ */
+static int __devlink_snapshot_id_insert(struct devlink *devlink, u32 id)
+{
+	int err;
+
+	xa_lock(&devlink->snapshot_ids);
+	if (xa_load(&devlink->snapshot_ids, id)) {
+		xa_unlock(&devlink->snapshot_ids);
+		return -EEXIST;
+	}
+	err = xa_err(__xa_store(&devlink->snapshot_ids, id, xa_mk_value(0),
+				GFP_ATOMIC));
+	xa_unlock(&devlink->snapshot_ids);
+	return err;
+}
+
+/**
+ *	__devlink_region_snapshot_id_get - get snapshot ID
+ *	@devlink: devlink instance
+ *	@id: storage to return snapshot id
+ *
+ *	Allocates a new snapshot id. Returns zero on success, or a negative
+ *	error on failure. Must be called while holding the devlink instance
+ *	lock.
+ *
+ *	Snapshot IDs are tracked using an xarray which stores the number of
+ *	users of the snapshot id.
+ *
+ *	Note that the caller of this function counts as a 'user', in order to
+ *	avoid race conditions. The caller must release its hold on the
+ *	snapshot by using devlink_region_snapshot_id_put.
+ */
+static int __devlink_region_snapshot_id_get(struct devlink *devlink, u32 *id)
+{
+	return xa_alloc(&devlink->snapshot_ids, id, xa_mk_value(1),
+			xa_limit_32b, GFP_KERNEL);
+}
+
+/**
+ *	__devlink_region_snapshot_create - create a new snapshot
+ *	This will add a new snapshot of a region. The snapshot
+ *	will be stored on the region struct and can be accessed
+ *	from devlink. This is useful for future analyses of snapshots.
+ *	Multiple snapshots can be created on a region.
+ *	The @snapshot_id should be obtained using the getter function.
+ *
+ *	Must be called only while holding the region snapshot lock.
+ *
+ *	@region: devlink region of the snapshot
+ *	@data: snapshot data
+ *	@snapshot_id: snapshot id to be created
+ */
+static int
+__devlink_region_snapshot_create(struct devlink_region *region,
+				 u8 *data, u32 snapshot_id)
+{
+	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot;
+	int err;
+
+	lockdep_assert_held(&region->snapshot_lock);
+
+	/* check if region can hold one more snapshot */
+	if (region->cur_snapshots == region->max_snapshots)
+		return -ENOSPC;
+
+	if (devlink_region_snapshot_get_by_id(region, snapshot_id))
+		return -EEXIST;
+
+	snapshot = kzalloc(sizeof(*snapshot), GFP_KERNEL);
+	if (!snapshot)
+		return -ENOMEM;
+
+	err = __devlink_snapshot_id_increment(devlink, snapshot_id);
+	if (err)
+		goto err_snapshot_id_increment;
+
+	snapshot->id = snapshot_id;
+	snapshot->region = region;
+	snapshot->data = data;
+
+	list_add_tail(&snapshot->list, &region->snapshot_list);
+
+	region->cur_snapshots++;
+
+	devlink_nl_region_notify(region, snapshot, DEVLINK_CMD_REGION_NEW);
+	return 0;
+
+err_snapshot_id_increment:
+	kfree(snapshot);
+	return err;
+}
+
+static void devlink_region_snapshot_del(struct devlink_region *region,
+					struct devlink_snapshot *snapshot)
+{
+	struct devlink *devlink = region->devlink;
+
+	lockdep_assert_held(&region->snapshot_lock);
+
+	devlink_nl_region_notify(region, snapshot, DEVLINK_CMD_REGION_DEL);
+	region->cur_snapshots--;
+	list_del(&snapshot->list);
+	region->ops->destructor(snapshot->data);
+	__devlink_snapshot_id_decrement(devlink, snapshot->id);
+	kfree(snapshot);
+}
+
+int devlink_nl_region_get_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_port *port = NULL;
+	struct devlink_region *region;
+	const char *region_name;
+	struct sk_buff *msg;
+	unsigned int index;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, DEVLINK_ATTR_REGION_NAME))
+		return -EINVAL;
+
+	if (info->attrs[DEVLINK_ATTR_PORT_INDEX]) {
+		index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
+
+		port = devlink_port_get_by_index(devlink, index);
+		if (!port)
+			return -ENODEV;
+	}
+
+	region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+	if (port)
+		region = devlink_port_region_get_by_name(port, region_name);
+	else
+		region = devlink_region_get_by_name(devlink, region_name);
+
+	if (!region)
+		return -EINVAL;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	err = devlink_nl_region_fill(msg, devlink, DEVLINK_CMD_REGION_GET,
+				     info->snd_portid, info->snd_seq, 0,
+				     region);
+	if (err) {
+		nlmsg_free(msg);
+		return err;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+
+static int devlink_nl_cmd_region_get_port_dumpit(struct sk_buff *msg,
+						 struct netlink_callback *cb,
+						 struct devlink_port *port,
+						 int *idx, int start, int flags)
+{
+	struct devlink_region *region;
+	int err = 0;
+
+	list_for_each_entry(region, &port->region_list, list) {
+		if (*idx < start) {
+			(*idx)++;
+			continue;
+		}
+		err = devlink_nl_region_fill(msg, port->devlink,
+					     DEVLINK_CMD_REGION_GET,
+					     NETLINK_CB(cb->skb).portid,
+					     cb->nlh->nlmsg_seq,
+					     flags, region);
+		if (err)
+			goto out;
+		(*idx)++;
+	}
+
+out:
+	return err;
+}
+
+static int devlink_nl_region_get_dump_one(struct sk_buff *msg,
+					  struct devlink *devlink,
+					  struct netlink_callback *cb,
+					  int flags)
+{
+	struct devlink_nl_dump_state *state = devlink_dump_state(cb);
+	struct devlink_region *region;
+	struct devlink_port *port;
+	unsigned long port_index;
+	int idx = 0;
+	int err;
+
+	list_for_each_entry(region, &devlink->region_list, list) {
+		if (idx < state->idx) {
+			idx++;
+			continue;
+		}
+		err = devlink_nl_region_fill(msg, devlink,
+					     DEVLINK_CMD_REGION_GET,
+					     NETLINK_CB(cb->skb).portid,
+					     cb->nlh->nlmsg_seq, flags,
+					     region);
+		if (err) {
+			state->idx = idx;
+			return err;
+		}
+		idx++;
+	}
+
+	xa_for_each(&devlink->ports, port_index, port) {
+		err = devlink_nl_cmd_region_get_port_dumpit(msg, cb, port, &idx,
+							    state->idx, flags);
+		if (err) {
+			state->idx = idx;
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+int devlink_nl_region_get_dumpit(struct sk_buff *skb,
+				 struct netlink_callback *cb)
+{
+	return devlink_nl_dumpit(skb, cb, devlink_nl_region_get_dump_one);
+}
+
+int devlink_nl_cmd_region_del(struct sk_buff *skb, struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_snapshot *snapshot;
+	struct devlink_port *port = NULL;
+	struct devlink_region *region;
+	const char *region_name;
+	unsigned int index;
+	u32 snapshot_id;
+
+	if (GENL_REQ_ATTR_CHECK(info, DEVLINK_ATTR_REGION_NAME) ||
+	    GENL_REQ_ATTR_CHECK(info, DEVLINK_ATTR_REGION_SNAPSHOT_ID))
+		return -EINVAL;
+
+	region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+	snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
+
+	if (info->attrs[DEVLINK_ATTR_PORT_INDEX]) {
+		index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
+
+		port = devlink_port_get_by_index(devlink, index);
+		if (!port)
+			return -ENODEV;
+	}
+
+	if (port)
+		region = devlink_port_region_get_by_name(port, region_name);
+	else
+		region = devlink_region_get_by_name(devlink, region_name);
+
+	if (!region)
+		return -EINVAL;
+
+	mutex_lock(&region->snapshot_lock);
+	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+	if (!snapshot) {
+		mutex_unlock(&region->snapshot_lock);
+		return -EINVAL;
+	}
+
+	devlink_region_snapshot_del(region, snapshot);
+	mutex_unlock(&region->snapshot_lock);
+	return 0;
+}
+
+int devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_snapshot *snapshot;
+	struct devlink_port *port = NULL;
+	struct nlattr *snapshot_id_attr;
+	struct devlink_region *region;
+	const char *region_name;
+	unsigned int index;
+	u32 snapshot_id;
+	u8 *data;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, DEVLINK_ATTR_REGION_NAME)) {
+		NL_SET_ERR_MSG(info->extack, "No region name provided");
+		return -EINVAL;
+	}
+
+	region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+
+	if (info->attrs[DEVLINK_ATTR_PORT_INDEX]) {
+		index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
+
+		port = devlink_port_get_by_index(devlink, index);
+		if (!port)
+			return -ENODEV;
+	}
+
+	if (port)
+		region = devlink_port_region_get_by_name(port, region_name);
+	else
+		region = devlink_region_get_by_name(devlink, region_name);
+
+	if (!region) {
+		NL_SET_ERR_MSG(info->extack, "The requested region does not exist");
+		return -EINVAL;
+	}
+
+	if (!region->ops->snapshot) {
+		NL_SET_ERR_MSG(info->extack, "The requested region does not support taking an immediate snapshot");
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&region->snapshot_lock);
+
+	if (region->cur_snapshots == region->max_snapshots) {
+		NL_SET_ERR_MSG(info->extack, "The region has reached the maximum number of stored snapshots");
+		err = -ENOSPC;
+		goto unlock;
+	}
+
+	snapshot_id_attr = info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID];
+	if (snapshot_id_attr) {
+		snapshot_id = nla_get_u32(snapshot_id_attr);
+
+		if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+			NL_SET_ERR_MSG(info->extack, "The requested snapshot id is already in use");
+			err = -EEXIST;
+			goto unlock;
+		}
+
+		err = __devlink_snapshot_id_insert(devlink, snapshot_id);
+		if (err)
+			goto unlock;
+	} else {
+		err = __devlink_region_snapshot_id_get(devlink, &snapshot_id);
+		if (err) {
+			NL_SET_ERR_MSG(info->extack, "Failed to allocate a new snapshot id");
+			goto unlock;
+		}
+	}
+
+	if (port)
+		err = region->port_ops->snapshot(port, region->port_ops,
+						 info->extack, &data);
+	else
+		err = region->ops->snapshot(devlink, region->ops,
+					    info->extack, &data);
+	if (err)
+		goto err_snapshot_capture;
+
+	err = __devlink_region_snapshot_create(region, data, snapshot_id);
+	if (err)
+		goto err_snapshot_create;
+
+	if (!snapshot_id_attr) {
+		struct sk_buff *msg;
+
+		snapshot = devlink_region_snapshot_get_by_id(region,
+							     snapshot_id);
+		if (WARN_ON(!snapshot)) {
+			err = -EINVAL;
+			goto unlock;
+		}
+
+		msg = devlink_nl_region_notify_build(region, snapshot,
+						     DEVLINK_CMD_REGION_NEW,
+						     info->snd_portid,
+						     info->snd_seq);
+		err = PTR_ERR_OR_ZERO(msg);
+		if (err)
+			goto err_notify;
+
+		err = genlmsg_reply(msg, info);
+		if (err)
+			goto err_notify;
+	}
+
+	mutex_unlock(&region->snapshot_lock);
+	return 0;
+
+err_snapshot_create:
+	region->ops->destructor(data);
+err_snapshot_capture:
+	__devlink_snapshot_id_decrement(devlink, snapshot_id);
+	mutex_unlock(&region->snapshot_lock);
+	return err;
+
+err_notify:
+	devlink_region_snapshot_del(region, snapshot);
+unlock:
+	mutex_unlock(&region->snapshot_lock);
+	return err;
+}
+
+static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg,
+						 u8 *chunk, u32 chunk_size,
+						 u64 addr)
+{
+	struct nlattr *chunk_attr;
+	int err;
+
+	chunk_attr = nla_nest_start_noflag(msg, DEVLINK_ATTR_REGION_CHUNK);
+	if (!chunk_attr)
+		return -EINVAL;
+
+	err = nla_put(msg, DEVLINK_ATTR_REGION_CHUNK_DATA, chunk_size, chunk);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_CHUNK_ADDR, addr,
+				DEVLINK_ATTR_PAD);
+	if (err)
+		goto nla_put_failure;
+
+	nla_nest_end(msg, chunk_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, chunk_attr);
+	return err;
+}
+
+#define DEVLINK_REGION_READ_CHUNK_SIZE 256
+
+typedef int devlink_chunk_fill_t(void *cb_priv, u8 *chunk, u32 chunk_size,
+				 u64 curr_offset,
+				 struct netlink_ext_ack *extack);
+
+static int
+devlink_nl_region_read_fill(struct sk_buff *skb, devlink_chunk_fill_t *cb,
+			    void *cb_priv, u64 start_offset, u64 end_offset,
+			    u64 *new_offset, struct netlink_ext_ack *extack)
+{
+	u64 curr_offset = start_offset;
+	int err = 0;
+	u8 *data;
+
+	/* Allocate and re-use a single buffer */
+	data = kmalloc(DEVLINK_REGION_READ_CHUNK_SIZE, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	*new_offset = start_offset;
+
+	while (curr_offset < end_offset) {
+		u32 data_size;
+
+		data_size = min_t(u32, end_offset - curr_offset,
+				  DEVLINK_REGION_READ_CHUNK_SIZE);
+
+		err = cb(cb_priv, data, data_size, curr_offset, extack);
+		if (err)
+			break;
+
+		err = devlink_nl_cmd_region_read_chunk_fill(skb, data, data_size, curr_offset);
+		if (err)
+			break;
+
+		curr_offset += data_size;
+	}
+	*new_offset = curr_offset;
+
+	kfree(data);
+
+	return err;
+}
+
+static int
+devlink_region_snapshot_fill(void *cb_priv, u8 *chunk, u32 chunk_size,
+			     u64 curr_offset,
+			     struct netlink_ext_ack __always_unused *extack)
+{
+	struct devlink_snapshot *snapshot = cb_priv;
+
+	memcpy(chunk, &snapshot->data[curr_offset], chunk_size);
+
+	return 0;
+}
+
+static int
+devlink_region_port_direct_fill(void *cb_priv, u8 *chunk, u32 chunk_size,
+				u64 curr_offset, struct netlink_ext_ack *extack)
+{
+	struct devlink_region *region = cb_priv;
+
+	return region->port_ops->read(region->port, region->port_ops, extack,
+				      curr_offset, chunk_size, chunk);
+}
+
+static int
+devlink_region_direct_fill(void *cb_priv, u8 *chunk, u32 chunk_size,
+			   u64 curr_offset, struct netlink_ext_ack *extack)
+{
+	struct devlink_region *region = cb_priv;
+
+	return region->ops->read(region->devlink, region->ops, extack,
+				 curr_offset, chunk_size, chunk);
+}
+
+int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
+				      struct netlink_callback *cb)
+{
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	struct devlink_nl_dump_state *state = devlink_dump_state(cb);
+	struct nlattr *chunks_attr, *region_attr, *snapshot_attr;
+	u64 ret_offset, start_offset, end_offset = U64_MAX;
+	struct nlattr **attrs = info->info.attrs;
+	struct devlink_port *port = NULL;
+	devlink_chunk_fill_t *region_cb;
+	struct devlink_region *region;
+	const char *region_name;
+	struct devlink *devlink;
+	unsigned int index;
+	void *region_cb_priv;
+	void *hdr;
+	int err;
+
+	start_offset = state->start_offset;
+
+	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
+	if (IS_ERR(devlink))
+		return PTR_ERR(devlink);
+
+	if (!attrs[DEVLINK_ATTR_REGION_NAME]) {
+		NL_SET_ERR_MSG(cb->extack, "No region name provided");
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (attrs[DEVLINK_ATTR_PORT_INDEX]) {
+		index = nla_get_u32(attrs[DEVLINK_ATTR_PORT_INDEX]);
+
+		port = devlink_port_get_by_index(devlink, index);
+		if (!port) {
+			err = -ENODEV;
+			goto out_unlock;
+		}
+	}
+
+	region_attr = attrs[DEVLINK_ATTR_REGION_NAME];
+	region_name = nla_data(region_attr);
+
+	if (port)
+		region = devlink_port_region_get_by_name(port, region_name);
+	else
+		region = devlink_region_get_by_name(devlink, region_name);
+
+	if (!region) {
+		NL_SET_ERR_MSG_ATTR(cb->extack, region_attr, "Requested region does not exist");
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	snapshot_attr = attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID];
+	if (!snapshot_attr) {
+		if (!nla_get_flag(attrs[DEVLINK_ATTR_REGION_DIRECT])) {
+			NL_SET_ERR_MSG(cb->extack, "No snapshot id provided");
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (!region->ops->read) {
+			NL_SET_ERR_MSG(cb->extack, "Requested region does not support direct read");
+			err = -EOPNOTSUPP;
+			goto out_unlock;
+		}
+
+		if (port)
+			region_cb = &devlink_region_port_direct_fill;
+		else
+			region_cb = &devlink_region_direct_fill;
+		region_cb_priv = region;
+	} else {
+		struct devlink_snapshot *snapshot;
+		u32 snapshot_id;
+
+		if (nla_get_flag(attrs[DEVLINK_ATTR_REGION_DIRECT])) {
+			NL_SET_ERR_MSG_ATTR(cb->extack, snapshot_attr, "Direct region read does not use snapshot");
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		snapshot_id = nla_get_u32(snapshot_attr);
+		snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+		if (!snapshot) {
+			NL_SET_ERR_MSG_ATTR(cb->extack, snapshot_attr, "Requested snapshot does not exist");
+			err = -EINVAL;
+			goto out_unlock;
+		}
+		region_cb = &devlink_region_snapshot_fill;
+		region_cb_priv = snapshot;
+	}
+
+	if (attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR] &&
+	    attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]) {
+		if (!start_offset)
+			start_offset =
+				nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR]);
+
+		end_offset = nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR]);
+		end_offset += nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]);
+	}
+
+	if (end_offset > region->size)
+		end_offset = region->size;
+
+	/* return 0 if there is no further data to read */
+	if (start_offset == end_offset) {
+		err = 0;
+		goto out_unlock;
+	}
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &devlink_nl_family, NLM_F_ACK | NLM_F_MULTI,
+			  DEVLINK_CMD_REGION_READ);
+	if (!hdr) {
+		err = -EMSGSIZE;
+		goto out_unlock;
+	}
+
+	err = devlink_nl_put_handle(skb, devlink);
+	if (err)
+		goto nla_put_failure;
+
+	if (region->port) {
+		err = nla_put_u32(skb, DEVLINK_ATTR_PORT_INDEX,
+				  region->port->index);
+		if (err)
+			goto nla_put_failure;
+	}
+
+	err = nla_put_string(skb, DEVLINK_ATTR_REGION_NAME, region_name);
+	if (err)
+		goto nla_put_failure;
+
+	chunks_attr = nla_nest_start_noflag(skb, DEVLINK_ATTR_REGION_CHUNKS);
+	if (!chunks_attr) {
+		err = -EMSGSIZE;
+		goto nla_put_failure;
+	}
+
+	err = devlink_nl_region_read_fill(skb, region_cb, region_cb_priv,
+					  start_offset, end_offset, &ret_offset,
+					  cb->extack);
+
+	if (err && err != -EMSGSIZE)
+		goto nla_put_failure;
+
+	/* Check if there was any progress done to prevent infinite loop */
+	if (ret_offset == start_offset) {
+		err = -EINVAL;
+		goto nla_put_failure;
+	}
+
+	state->start_offset = ret_offset;
+
+	nla_nest_end(skb, chunks_attr);
+	genlmsg_end(skb, hdr);
+	devl_unlock(devlink);
+	devlink_put(devlink);
+	return skb->len;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+out_unlock:
+	devl_unlock(devlink);
+	devlink_put(devlink);
+	return err;
+}
+
+/**
+ * devl_region_create - create a new address region
+ *
+ * @devlink: devlink
+ * @ops: region operations and name
+ * @region_max_snapshots: Maximum supported number of snapshots for region
+ * @region_size: size of region
+ */
+struct devlink_region *devl_region_create(struct devlink *devlink,
+					  const struct devlink_region_ops *ops,
+					  u32 region_max_snapshots,
+					  u64 region_size)
+{
+	struct devlink_region *region;
+
+	devl_assert_locked(devlink);
+
+	if (WARN_ON(!ops) || WARN_ON(!ops->destructor))
+		return ERR_PTR(-EINVAL);
+
+	if (devlink_region_get_by_name(devlink, ops->name))
+		return ERR_PTR(-EEXIST);
+
+	region = kzalloc(sizeof(*region), GFP_KERNEL);
+	if (!region)
+		return ERR_PTR(-ENOMEM);
+
+	region->devlink = devlink;
+	region->max_snapshots = region_max_snapshots;
+	region->ops = ops;
+	region->size = region_size;
+	INIT_LIST_HEAD(&region->snapshot_list);
+	mutex_init(&region->snapshot_lock);
+	list_add_tail(&region->list, &devlink->region_list);
+	devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);
+
+	return region;
+}
+EXPORT_SYMBOL_GPL(devl_region_create);
+
+/**
+ *	devlink_region_create - create a new address region
+ *
+ *	@devlink: devlink
+ *	@ops: region operations and name
+ *	@region_max_snapshots: Maximum supported number of snapshots for region
+ *	@region_size: size of region
+ *
+ *	Context: Takes and release devlink->lock <mutex>.
+ */
+struct devlink_region *
+devlink_region_create(struct devlink *devlink,
+		      const struct devlink_region_ops *ops,
+		      u32 region_max_snapshots, u64 region_size)
+{
+	struct devlink_region *region;
+
+	devl_lock(devlink);
+	region = devl_region_create(devlink, ops, region_max_snapshots,
+				    region_size);
+	devl_unlock(devlink);
+	return region;
+}
+EXPORT_SYMBOL_GPL(devlink_region_create);
+
+/**
+ *	devlink_port_region_create - create a new address region for a port
+ *
+ *	@port: devlink port
+ *	@ops: region operations and name
+ *	@region_max_snapshots: Maximum supported number of snapshots for region
+ *	@region_size: size of region
+ *
+ *	Context: Takes and release devlink->lock <mutex>.
+ */
+struct devlink_region *
+devlink_port_region_create(struct devlink_port *port,
+			   const struct devlink_port_region_ops *ops,
+			   u32 region_max_snapshots, u64 region_size)
+{
+	struct devlink *devlink = port->devlink;
+	struct devlink_region *region;
+	int err = 0;
+
+	ASSERT_DEVLINK_PORT_INITIALIZED(port);
+
+	if (WARN_ON(!ops) || WARN_ON(!ops->destructor))
+		return ERR_PTR(-EINVAL);
+
+	devl_lock(devlink);
+
+	if (devlink_port_region_get_by_name(port, ops->name)) {
+		err = -EEXIST;
+		goto unlock;
+	}
+
+	region = kzalloc(sizeof(*region), GFP_KERNEL);
+	if (!region) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	region->devlink = devlink;
+	region->port = port;
+	region->max_snapshots = region_max_snapshots;
+	region->port_ops = ops;
+	region->size = region_size;
+	INIT_LIST_HEAD(&region->snapshot_list);
+	mutex_init(&region->snapshot_lock);
+	list_add_tail(&region->list, &port->region_list);
+	devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);
+
+	devl_unlock(devlink);
+	return region;
+
+unlock:
+	devl_unlock(devlink);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(devlink_port_region_create);
+
+/**
+ * devl_region_destroy - destroy address region
+ *
+ * @region: devlink region to destroy
+ */
+void devl_region_destroy(struct devlink_region *region)
+{
+	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot, *ts;
+
+	devl_assert_locked(devlink);
+
+	/* Free all snapshots of region */
+	mutex_lock(&region->snapshot_lock);
+	list_for_each_entry_safe(snapshot, ts, &region->snapshot_list, list)
+		devlink_region_snapshot_del(region, snapshot);
+	mutex_unlock(&region->snapshot_lock);
+
+	list_del(&region->list);
+	mutex_destroy(&region->snapshot_lock);
+
+	devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_DEL);
+	kfree(region);
+}
+EXPORT_SYMBOL_GPL(devl_region_destroy);
+
+/**
+ *	devlink_region_destroy - destroy address region
+ *
+ *	@region: devlink region to destroy
+ *
+ *	Context: Takes and release devlink->lock <mutex>.
+ */
+void devlink_region_destroy(struct devlink_region *region)
+{
+	struct devlink *devlink = region->devlink;
+
+	devl_lock(devlink);
+	devl_region_destroy(region);
+	devl_unlock(devlink);
+}
+EXPORT_SYMBOL_GPL(devlink_region_destroy);
+
+/**
+ *	devlink_region_snapshot_id_get - get snapshot ID
+ *
+ *	This callback should be called when adding a new snapshot,
+ *	Driver should use the same id for multiple snapshots taken
+ *	on multiple regions at the same time/by the same trigger.
+ *
+ *	The caller of this function must use devlink_region_snapshot_id_put
+ *	when finished creating regions using this id.
+ *
+ *	Returns zero on success, or a negative error code on failure.
+ *
+ *	@devlink: devlink
+ *	@id: storage to return id
+ */
+int devlink_region_snapshot_id_get(struct devlink *devlink, u32 *id)
+{
+	return __devlink_region_snapshot_id_get(devlink, id);
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_id_get);
+
+/**
+ *	devlink_region_snapshot_id_put - put snapshot ID reference
+ *
+ *	This should be called by a driver after finishing creating snapshots
+ *	with an id. Doing so ensures that the ID can later be released in the
+ *	event that all snapshots using it have been destroyed.
+ *
+ *	@devlink: devlink
+ *	@id: id to release reference on
+ */
+void devlink_region_snapshot_id_put(struct devlink *devlink, u32 id)
+{
+	__devlink_snapshot_id_decrement(devlink, id);
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_id_put);
+
+/**
+ *	devlink_region_snapshot_create - create a new snapshot
+ *	This will add a new snapshot of a region. The snapshot
+ *	will be stored on the region struct and can be accessed
+ *	from devlink. This is useful for future analyses of snapshots.
+ *	Multiple snapshots can be created on a region.
+ *	The @snapshot_id should be obtained using the getter function.
+ *
+ *	@region: devlink region of the snapshot
+ *	@data: snapshot data
+ *	@snapshot_id: snapshot id to be created
+ */
+int devlink_region_snapshot_create(struct devlink_region *region,
+				   u8 *data, u32 snapshot_id)
+{
+	int err;
+
+	mutex_lock(&region->snapshot_lock);
+	err = __devlink_region_snapshot_create(region, data, snapshot_id);
+	mutex_unlock(&region->snapshot_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_create);