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net: devlink: take RTNL in port_fill() function only if it is not held
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Follow-up patch is going to introduce a netdevice notifier event
processing which is called with RTNL mutex held. Processing of this will
eventually lead to call to port_notity() and port_fill() which currently
takes RTNL mutex internally. So as a temporary solution, propagate a
bool indicating if the mutex is already held. This will go away in one
of the follow-up patches.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Jiri Pirko authored and Jakub Kicinski committed Nov 4, 2022
1 parent 45791e0 commit d41c9db
Showing 1 changed file with 31 additions and 15 deletions.
46 changes: 31 additions & 15 deletions net/core/devlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1278,7 +1278,8 @@ devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *por
static int devlink_nl_port_fill(struct sk_buff *msg,
struct devlink_port *devlink_port,
enum devlink_command cmd, u32 portid, u32 seq,
int flags, struct netlink_ext_ack *extack)
int flags, struct netlink_ext_ack *extack,
bool rtnl_held)
{
struct devlink *devlink = devlink_port->devlink;
void *hdr;
Expand All @@ -1293,7 +1294,8 @@ static int devlink_nl_port_fill(struct sk_buff *msg,
goto nla_put_failure;

/* Hold rtnl lock while accessing port's netdev attributes. */
rtnl_lock();
if (!rtnl_held)
rtnl_lock();
spin_lock_bh(&devlink_port->type_lock);
if (nla_put_u16(msg, DEVLINK_ATTR_PORT_TYPE, devlink_port->type))
goto nla_put_failure_type_locked;
Expand Down Expand Up @@ -1321,7 +1323,8 @@ static int devlink_nl_port_fill(struct sk_buff *msg,
goto nla_put_failure_type_locked;
}
spin_unlock_bh(&devlink_port->type_lock);
rtnl_unlock();
if (!rtnl_held)
rtnl_unlock();
if (devlink_nl_port_attrs_put(msg, devlink_port))
goto nla_put_failure;
if (devlink_nl_port_function_attrs_put(msg, devlink_port, extack))
Expand All @@ -1336,14 +1339,15 @@ static int devlink_nl_port_fill(struct sk_buff *msg,

nla_put_failure_type_locked:
spin_unlock_bh(&devlink_port->type_lock);
rtnl_unlock();
if (!rtnl_held)
rtnl_unlock();
nla_put_failure:
genlmsg_cancel(msg, hdr);
return -EMSGSIZE;
}

static void devlink_port_notify(struct devlink_port *devlink_port,
enum devlink_command cmd)
static void __devlink_port_notify(struct devlink_port *devlink_port,
enum devlink_command cmd, bool rtnl_held)
{
struct devlink *devlink = devlink_port->devlink;
struct sk_buff *msg;
Expand All @@ -1358,7 +1362,8 @@ static void devlink_port_notify(struct devlink_port *devlink_port,
if (!msg)
return;

err = devlink_nl_port_fill(msg, devlink_port, cmd, 0, 0, 0, NULL);
err = devlink_nl_port_fill(msg, devlink_port, cmd, 0, 0, 0, NULL,
rtnl_held);
if (err) {
nlmsg_free(msg);
return;
Expand All @@ -1368,6 +1373,12 @@ static void devlink_port_notify(struct devlink_port *devlink_port,
0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
}

static void devlink_port_notify(struct devlink_port *devlink_port,
enum devlink_command cmd)
{
__devlink_port_notify(devlink_port, cmd, false);
}

static void devlink_rate_notify(struct devlink_rate *devlink_rate,
enum devlink_command cmd)
{
Expand Down Expand Up @@ -1531,7 +1542,7 @@ static int devlink_nl_cmd_port_get_doit(struct sk_buff *skb,

err = devlink_nl_port_fill(msg, devlink_port, DEVLINK_CMD_PORT_NEW,
info->snd_portid, info->snd_seq, 0,
info->extack);
info->extack, false);
if (err) {
nlmsg_free(msg);
return err;
Expand Down Expand Up @@ -1561,7 +1572,8 @@ static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
DEVLINK_CMD_NEW,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NLM_F_MULTI, cb->extack);
NLM_F_MULTI, cb->extack,
false);
if (err) {
devl_unlock(devlink);
devlink_put(devlink);
Expand Down Expand Up @@ -1773,7 +1785,8 @@ static int devlink_port_new_notify(struct devlink *devlink,
}

err = devlink_nl_port_fill(msg, devlink_port, DEVLINK_CMD_NEW,
info->snd_portid, info->snd_seq, 0, NULL);
info->snd_portid, info->snd_seq, 0, NULL,
false);
if (err)
goto out;

Expand Down Expand Up @@ -10033,7 +10046,7 @@ static void devlink_port_type_netdev_checks(struct devlink_port *devlink_port,

static void __devlink_port_type_set(struct devlink_port *devlink_port,
enum devlink_port_type type,
void *type_dev)
void *type_dev, bool rtnl_held)
{
struct net_device *netdev = type_dev;

Expand All @@ -10060,7 +10073,7 @@ static void __devlink_port_type_set(struct devlink_port *devlink_port,
break;
}
spin_unlock_bh(&devlink_port->type_lock);
devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
__devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW, rtnl_held);
}

/**
Expand All @@ -10077,7 +10090,8 @@ void devlink_port_type_eth_set(struct devlink_port *devlink_port,
"devlink port type for port %d set to Ethernet without a software interface reference, device type not supported by the kernel?\n",
devlink_port->index);

__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH, netdev);
__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH, netdev,
false);
}
EXPORT_SYMBOL_GPL(devlink_port_type_eth_set);

Expand All @@ -10090,7 +10104,8 @@ EXPORT_SYMBOL_GPL(devlink_port_type_eth_set);
void devlink_port_type_ib_set(struct devlink_port *devlink_port,
struct ib_device *ibdev)
{
__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_IB, ibdev);
__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_IB, ibdev,
false);
}
EXPORT_SYMBOL_GPL(devlink_port_type_ib_set);

Expand All @@ -10101,7 +10116,8 @@ EXPORT_SYMBOL_GPL(devlink_port_type_ib_set);
*/
void devlink_port_type_clear(struct devlink_port *devlink_port)
{
__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_NOTSET, NULL);
__devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_NOTSET, NULL,
false);
}
EXPORT_SYMBOL_GPL(devlink_port_type_clear);

Expand Down

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