devlink: add by-instance dump infra

Most dumpit implementations walk the devlink instances.
This requires careful lock taking and reference dropping.
Factor the loop out and provide just a callback to handle
a single instance dump.

Convert one user as an example, other users converted
in the next change.

Slightly inspired by ethtool netlink code.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2023-01-04 20:05:30 -08:00
parent e4d5015bc1
commit 07f3af6608
3 changed files with 68 additions and 31 deletions

View File

@ -122,6 +122,11 @@ struct devlink_nl_dump_state {
};
};
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.
@ -140,6 +145,9 @@ 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)
{
@ -175,6 +183,8 @@ 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 *

View File

@ -1219,47 +1219,40 @@ static void devlink_rate_notify(struct devlink_rate *devlink_rate,
0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
}
static int devlink_nl_cmd_rate_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
static int
devlink_nl_cmd_rate_get_dump_one(struct sk_buff *msg, struct devlink *devlink,
struct netlink_callback *cb)
{
struct devlink_nl_dump_state *state = devlink_dump_state(cb);
struct devlink *devlink;
struct devlink_rate *devlink_rate;
int idx = 0;
int err = 0;
devlink_dump_for_each_instance_get(msg, state, devlink) {
struct devlink_rate *devlink_rate;
int idx = 0;
list_for_each_entry(devlink_rate, &devlink->rate_list, list) {
enum devlink_command cmd = DEVLINK_CMD_RATE_NEW;
u32 id = NETLINK_CB(cb->skb).portid;
devl_lock(devlink);
list_for_each_entry(devlink_rate, &devlink->rate_list, list) {
enum devlink_command cmd = DEVLINK_CMD_RATE_NEW;
u32 id = NETLINK_CB(cb->skb).portid;
if (idx < state->idx) {
idx++;
continue;
}
err = devlink_nl_rate_fill(msg, devlink_rate, cmd, id,
cb->nlh->nlmsg_seq,
NLM_F_MULTI, NULL);
if (err) {
devl_unlock(devlink);
devlink_put(devlink);
state->idx = idx;
goto out;
}
if (idx < state->idx) {
idx++;
continue;
}
devl_unlock(devlink);
devlink_put(devlink);
err = devlink_nl_rate_fill(msg, devlink_rate, cmd, id,
cb->nlh->nlmsg_seq,
NLM_F_MULTI, NULL);
if (err) {
state->idx = idx;
break;
}
idx++;
}
out:
if (err != -EMSGSIZE)
return err;
return msg->len;
return err;
}
const struct devlink_gen_cmd devl_gen_rate_get = {
.dump_one = devlink_nl_cmd_rate_get_dump_one,
};
static int devlink_nl_cmd_rate_get_doit(struct sk_buff *skb,
struct genl_info *info)
{
@ -9130,7 +9123,7 @@ const struct genl_small_ops devlink_nl_ops[56] = {
{
.cmd = DEVLINK_CMD_RATE_GET,
.doit = devlink_nl_cmd_rate_get_doit,
.dumpit = devlink_nl_cmd_rate_get_dumpit,
.dumpit = devlink_nl_instance_iter_dump,
.internal_flags = DEVLINK_NL_FLAG_NEED_RATE,
/* can be retrieved by unprivileged users */
},

View File

@ -5,6 +5,7 @@
*/
#include <net/genetlink.h>
#include <net/sock.h>
#include "devl_internal.h"
@ -177,6 +178,39 @@ static void devlink_nl_post_doit(const struct genl_split_ops *ops,
devlink_put(devlink);
}
static const struct devlink_gen_cmd *devl_gen_cmds[] = {
[DEVLINK_CMD_RATE_GET] = &devl_gen_rate_get,
};
int devlink_nl_instance_iter_dump(struct sk_buff *msg,
struct netlink_callback *cb)
{
const struct genl_dumpit_info *info = genl_dumpit_info(cb);
struct devlink_nl_dump_state *state = devlink_dump_state(cb);
const struct devlink_gen_cmd *cmd;
struct devlink *devlink;
int err = 0;
cmd = devl_gen_cmds[info->op.cmd];
devlink_dump_for_each_instance_get(msg, state, devlink) {
devl_lock(devlink);
err = cmd->dump_one(msg, devlink, cb);
devl_unlock(devlink);
devlink_put(devlink);
if (err)
break;
/* restart sub-object walk for the next instance */
state->idx = 0;
}
if (err != -EMSGSIZE)
return err;
return msg->len;
}
struct genl_family devlink_nl_family __ro_after_init = {
.name = DEVLINK_GENL_NAME,
.version = DEVLINK_GENL_VERSION,