[PATCH net-next 05/14] devlink: use an explicit structure for dump context

Jakub Kicinski
2023-01-04T04:17:11Z

Create a dump context structure instead of using cb->args
as an unsigned long array. This is a pure conversion which
is intended to be as much of a noop as possible.
Subsequent changes will use this to simplify the code.

The two non-trivial parts are:
- devlink_nl_cmd_health_reporter_dump_get_dumpit() checks args[0]
to see if devlink_fmsg_dumpit() has already been called (whether
this is the first msg), but doesn't use the exact value, so we
can drop the local variable there already
- devlink_nl_cmd_region_read_dumpit() uses args[0] for address
but we'll use args[1] now, shouldn't matter

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/devlink/devl_internal.h | 23 +++++++++
net/devlink/leftover.c | 98 ++++++++++++++++++++++---------------
2 files changed, 81 insertions(+), 40 deletions(-)

diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
index bc7df9b0f775..91059311f18d 100644
--- a/net/devlink/devl_internal.h
+++ b/net/devlink/devl_internal.h
@@ -107,6 +107,21 @@ enum devlink_multicast_groups {
DEVLINK_MCGRP_CONFIG,
};

+/* state held across netlink dumps */
+struct devlink_nl_dump_state {
+ int idx;
+ union {
+ /* DEVLINK_CMD_REGION_READ */
+ struct {
+ u64 start_offset;
+ };
+ /* DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET */
+ struct {
+ u64 dump_ts;
+ };
+ };
+};
+
extern const struct genl_small_ops devlink_nl_ops[56];

struct devlink *devlink_get_from_attrs(struct net *net, struct nlattr **attrs);
@@ -114,6 +129,14 @@ 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);

+static inline struct devlink_nl_dump_state *
+devl_dump_state(struct netlink_callback *cb)
+{
+ NL_ASSET_DUMP_CTX_FITS(struct devlink_nl_dump_state);
+
+ return (struct devlink_nl_dump_state *)cb->ctx;
+}
+
/* Ports */
int devlink_port_netdevice_event(struct notifier_block *nb,
unsigned long event, void *ptr);
diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index e01ba7999b91..bcc930b7cfcf 100644
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -1222,9 +1222,10 @@ static void devlink_rate_notify(struct devlink_rate *devlink_rate,
static int devlink_nl_cmd_rate_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_rate *devlink_rate;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -1256,7 +1257,7 @@ static int devlink_nl_cmd_rate_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -1317,8 +1318,9 @@ static int devlink_nl_cmd_get_doit(struct sk_buff *skb, struct genl_info *info)
static int devlink_nl_cmd_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -1342,7 +1344,7 @@ static int devlink_nl_cmd_get_dumpit(struct sk_buff *msg,
idx++;
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -1371,10 +1373,11 @@ static int devlink_nl_cmd_port_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
struct devlink_port *devlink_port;
unsigned long index, port_index;
- int start = cb->args[0];
+ int start = dump->idx;
int idx = 0;
int err;

@@ -1401,7 +1404,7 @@ static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -2150,9 +2153,10 @@ static int devlink_nl_cmd_linecard_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_linecard *linecard;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -2183,7 +2187,7 @@ static int devlink_nl_cmd_linecard_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -2412,9 +2416,10 @@ static int devlink_nl_cmd_sb_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_sb_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
struct devlink_sb *devlink_sb;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -2442,7 +2447,7 @@ static int devlink_nl_cmd_sb_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -2554,9 +2559,10 @@ static int __sb_pool_get_dumpit(struct sk_buff *msg, int start, int *p_idx,
static int devlink_nl_cmd_sb_pool_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
struct devlink_sb *devlink_sb;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -2587,7 +2593,7 @@ static int devlink_nl_cmd_sb_pool_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -2769,9 +2775,10 @@ static int __sb_port_pool_get_dumpit(struct sk_buff *msg, int start, int *p_idx,
static int devlink_nl_cmd_sb_port_pool_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
struct devlink_sb *devlink_sb;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -2802,7 +2809,7 @@ static int devlink_nl_cmd_sb_port_pool_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -3012,9 +3019,10 @@ static int
devlink_nl_cmd_sb_tc_pool_bind_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
struct devlink_sb *devlink_sb;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -3046,7 +3054,7 @@ devlink_nl_cmd_sb_tc_pool_bind_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -4871,8 +4879,9 @@ static int devlink_nl_cmd_selftests_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_selftests_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -4899,7 +4908,7 @@ static int devlink_nl_cmd_selftests_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -5351,9 +5360,10 @@ static void devlink_param_notify(struct devlink *devlink,
static int devlink_nl_cmd_param_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_param_item *param_item;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -5386,7 +5396,7 @@ static int devlink_nl_cmd_param_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -6095,8 +6105,9 @@ static int devlink_nl_cmd_region_get_devlink_dumpit(struct sk_buff *msg,
static int devlink_nl_cmd_region_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -6109,7 +6120,7 @@ static int devlink_nl_cmd_region_get_dumpit(struct sk_buff *msg,
goto out;
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -6394,6 +6405,7 @@ static 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 *dump = devl_dump_state(cb);
struct nlattr *chunks_attr, *region_attr, *snapshot_attr;
u64 ret_offset, start_offset, end_offset = U64_MAX;
struct nlattr **attrs = info->attrs;
@@ -6407,7 +6419,7 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
void *hdr;
int err;

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

devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
if (IS_ERR(devlink))
@@ -6546,7 +6558,7 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
goto nla_put_failure;
}

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

nla_nest_end(skb, chunks_attr);
genlmsg_end(skb, hdr);
@@ -6745,8 +6757,9 @@ static int devlink_nl_cmd_info_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_info_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err = 0;
@@ -6775,7 +6788,7 @@ static int devlink_nl_cmd_info_get_dumpit(struct sk_buff *msg,
if (err != -EMSGSIZE)
return err;

- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -7344,7 +7357,8 @@ static int devlink_fmsg_dumpit(struct devlink_fmsg *fmsg, struct sk_buff *skb,
struct netlink_callback *cb,
enum devlink_command cmd)
{
- int index = cb->args[0];
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
+ int index = dump->idx;
int tmp_index = index;
void *hdr;
int err;
@@ -7360,7 +7374,7 @@ static int devlink_fmsg_dumpit(struct devlink_fmsg *fmsg, struct sk_buff *skb,
if ((err && err != -EMSGSIZE) || tmp_index == index)
goto nla_put_failure;

- cb->args[0] = index;
+ dump->idx = index;
genlmsg_end(skb, hdr);
return skb->len;

@@ -7911,11 +7925,12 @@ static int
devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_health_reporter *reporter;
unsigned long index, port_index;
struct devlink_port *port;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
int idx = 0;
int err;

@@ -7970,7 +7985,7 @@ devlink_nl_cmd_health_reporter_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -8082,8 +8097,8 @@ static int
devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_health_reporter *reporter;
- u64 start = cb->args[0];
int err;

reporter = devlink_health_reporter_get_from_cb(cb);
@@ -8095,13 +8110,13 @@ devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
goto out;
}
mutex_lock(&reporter->dump_lock);
- if (!start) {
+ if (!dump->idx) {
err = devlink_health_do_dump(reporter, NULL, cb->extack);
if (err)
goto unlock;
- cb->args[1] = reporter->dump_ts;
+ dump->dump_ts = reporter->dump_ts;
}
- if (!reporter->dump_fmsg || cb->args[1] != reporter->dump_ts) {
+ if (!reporter->dump_fmsg || dump->dump_ts != reporter->dump_ts) {
NL_SET_ERR_MSG_MOD(cb->extack, "Dump trampled, please retry");
err = -EAGAIN;
goto unlock;
@@ -8495,9 +8510,10 @@ static int devlink_nl_cmd_trap_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_trap_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
struct devlink_trap_item *trap_item;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -8525,7 +8541,7 @@ static int devlink_nl_cmd_trap_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -8710,11 +8726,12 @@ static int devlink_nl_cmd_trap_group_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_trap_group_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
enum devlink_command cmd = DEVLINK_CMD_TRAP_GROUP_NEW;
struct devlink_trap_group_item *group_item;
u32 portid = NETLINK_CB(cb->skb).portid;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -8743,7 +8760,7 @@ static int devlink_nl_cmd_trap_group_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

@@ -9014,11 +9031,12 @@ static int devlink_nl_cmd_trap_policer_get_doit(struct sk_buff *skb,
static int devlink_nl_cmd_trap_policer_get_dumpit(struct sk_buff *msg,
struct netlink_callback *cb)
{
+ struct devlink_nl_dump_state *dump = devl_dump_state(cb);
enum devlink_command cmd = DEVLINK_CMD_TRAP_POLICER_NEW;
struct devlink_trap_policer_item *policer_item;
u32 portid = NETLINK_CB(cb->skb).portid;
struct devlink *devlink;
- int start = cb->args[0];
+ int start = dump->idx;
unsigned long index;
int idx = 0;
int err;
@@ -9047,7 +9065,7 @@ static int devlink_nl_cmd_trap_policer_get_dumpit(struct sk_buff *msg,
devlink_put(devlink);
}
out:
- cb->args[0] = idx;
+ dump->idx = idx;
return msg->len;
}

--
2.38.1