Commit 4e54795a authored by Alex Vesker's avatar Alex Vesker Committed by David S. Miller
Browse files

devlink: Add support for region snapshot read command 



Add support for DEVLINK_CMD_REGION_READ_GET used for both reading
and dumping region data. Read allows reading from a region specific
address for given length. Dump allows reading the full region.
If only snapshot ID is provided a snapshot dump will be done.
If snapshot ID, Address and Length are provided a snapshot read
will done.

This is used for both snapshot access and will be used in the same
way to access current data on the region.

Signed-off-by: default avatarAlex Vesker <valex@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 866319bb

include/uapi/linux/devlink.h

+7 −0
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ enum devlink_command { 
	DEVLINK_CMD_REGION_SET,

	DEVLINK_CMD_REGION_NEW,

	DEVLINK_CMD_REGION_DEL,

	DEVLINK_CMD_REGION_READ,



	/* add new commands above here */

	__DEVLINK_CMD_MAX,
@@ -273,6 +274,12 @@ enum devlink_attr { 
	DEVLINK_ATTR_REGION_SNAPSHOT,           /* nested */

	DEVLINK_ATTR_REGION_SNAPSHOT_ID,        /* u32 */



	DEVLINK_ATTR_REGION_CHUNKS,             /* nested */

	DEVLINK_ATTR_REGION_CHUNK,              /* nested */

	DEVLINK_ATTR_REGION_CHUNK_DATA,         /* binary */

	DEVLINK_ATTR_REGION_CHUNK_ADDR,         /* u64 */

	DEVLINK_ATTR_REGION_CHUNK_LEN,          /* u64 */



	/* add new attributes above here, update the policy in devlink.c */



	__DEVLINK_ATTR_MAX,

net/core/devlink.c

+182 −0
Original line number Diff line number Diff line
@@ -3388,6 +3388,181 @@ static int devlink_nl_cmd_region_del(struct sk_buff *skb, 
	return 0;

}



static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg,

						 struct devlink *devlink,

						 u8 *chunk, u32 chunk_size,

						 u64 addr)

{

	struct nlattr *chunk_attr;

	int err;



	chunk_attr = nla_nest_start(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



static int devlink_nl_region_read_snapshot_fill(struct sk_buff *skb,

						struct devlink *devlink,

						struct devlink_region *region,

						struct nlattr **attrs,

						u64 start_offset,

						u64 end_offset,

						bool dump,

						u64 *new_offset)

{

	struct devlink_snapshot *snapshot;

	u64 curr_offset = start_offset;

	u32 snapshot_id;

	int err = 0;



	*new_offset = start_offset;



	snapshot_id = nla_get_u32(attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);

	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);

	if (!snapshot)

		return -EINVAL;



	if (end_offset > snapshot->data_len || dump)

		end_offset = snapshot->data_len;



	while (curr_offset < end_offset) {

		u32 data_size;

		u8 *data;



		if (end_offset - curr_offset < DEVLINK_REGION_READ_CHUNK_SIZE)

			data_size = end_offset - curr_offset;

		else

			data_size = DEVLINK_REGION_READ_CHUNK_SIZE;



		data = &snapshot->data[curr_offset];

		err = devlink_nl_cmd_region_read_chunk_fill(skb, devlink,

							    data, data_size,

							    curr_offset);

		if (err)

			break;



		curr_offset += data_size;

	}

	*new_offset = curr_offset;



	return err;

}



static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,

					     struct netlink_callback *cb)

{

	u64 ret_offset, start_offset, end_offset = 0;

	struct nlattr *attrs[DEVLINK_ATTR_MAX + 1];

	const struct genl_ops *ops = cb->data;

	struct devlink_region *region;

	struct nlattr *chunks_attr;

	const char *region_name;

	struct devlink *devlink;

	bool dump = true;

	void *hdr;

	int err;



	start_offset = *((u64 *)&cb->args[0]);



	err = nlmsg_parse(cb->nlh, GENL_HDRLEN + devlink_nl_family.hdrsize,

			  attrs, DEVLINK_ATTR_MAX, ops->policy, NULL);

	if (err)

		goto out;



	devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);

	if (IS_ERR(devlink))

		goto out;



	mutex_lock(&devlink_mutex);

	mutex_lock(&devlink->lock);



	if (!attrs[DEVLINK_ATTR_REGION_NAME] ||

	    !attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID])

		goto out_unlock;



	region_name = nla_data(attrs[DEVLINK_ATTR_REGION_NAME]);

	region = devlink_region_get_by_name(devlink, region_name);

	if (!region)

		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)

		goto out_unlock;



	err = devlink_nl_put_handle(skb, devlink);

	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(skb, DEVLINK_ATTR_REGION_CHUNKS);

	if (!chunks_attr)

		goto nla_put_failure;



	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]);

		dump = false;

	}



	err = devlink_nl_region_read_snapshot_fill(skb, devlink,

						   region, attrs,

						   start_offset,

						   end_offset, dump,

						   &ret_offset);



	if (err && err != -EMSGSIZE)

		goto nla_put_failure;



	/* Check if there was any progress done to prevent infinite loop */

	if (ret_offset == start_offset)

		goto nla_put_failure;



	*((u64 *)&cb->args[0]) = ret_offset;



	nla_nest_end(skb, chunks_attr);

	genlmsg_end(skb, hdr);

	mutex_unlock(&devlink->lock);

	mutex_unlock(&devlink_mutex);



	return skb->len;



nla_put_failure:

	genlmsg_cancel(skb, hdr);

out_unlock:

	mutex_unlock(&devlink->lock);

	mutex_unlock(&devlink_mutex);

out:

	return 0;

}



static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {

	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },

	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
@@ -3626,6 +3801,13 @@ static const struct genl_ops devlink_nl_ops[] = { 
		.flags = GENL_ADMIN_PERM,

		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,

	},

	{

		.cmd = DEVLINK_CMD_REGION_READ,

		.dumpit = devlink_nl_cmd_region_read_dumpit,

		.policy = devlink_nl_policy,

		.flags = GENL_ADMIN_PERM,

		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,

	},

};



static struct genl_family devlink_nl_family __ro_after_init = {

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