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net-sysfs: convert dev->operstate reads to lockless ones 

[ Upstream commit 004d138364 ]

operstate_show() can omit dev_base_lock acquisition only
to read dev->operstate.

Annotate accesses to dev->operstate.

Writers still acquire dev_base_lock for mutual exclusion.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 4893b8b3ef ("hsr: Simplify code for announcing HSR nodes timer setup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Dumazet 2024-02-13 06:32:39 +00:00 committed by Greg Kroah-Hartman
parent 1876881c9a
commit ec87ec591e
6 changed files with 13 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/bridge/br_netlink.c
View File

@ -455,7 +455,8 @@ static int br_fill_ifinfo(struct sk_buff *skb,
u32 filter_mask, const struct net_device *dev,
bool getlink)
{
u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
u8 operstate = netif_running(dev) ? READ_ONCE(dev->operstate) :
IF_OPER_DOWN;
struct nlattr *af = NULL;
struct net_bridge *br;
struct ifinfomsg *hdr;

4
net/core/link_watch.c
View File

@ -67,7 +67,7 @@ static void rfc2863_policy(struct net_device *dev)
{
unsigned char operstate = default_operstate(dev);
if (operstate == dev->operstate)
if (operstate == READ_ONCE(dev->operstate))
return;
write_lock(&dev_base_lock);
@ -87,7 +87,7 @@ static void rfc2863_policy(struct net_device *dev)
break;
}
dev->operstate = operstate;
WRITE_ONCE(dev->operstate, operstate);
write_unlock(&dev_base_lock);
}

4
net/core/net-sysfs.c
View File

@ -318,11 +318,9 @@ static ssize_t operstate_show(struct device *dev,
const struct net_device *netdev = to_net_dev(dev);
unsigned char operstate;
read_lock(&dev_base_lock);
operstate = netdev->operstate;
operstate = READ_ONCE(netdev->operstate);
if (!netif_running(netdev))
operstate = IF_OPER_DOWN;
read_unlock(&dev_base_lock);
if (operstate >= ARRAY_SIZE(operstates))
return -EINVAL; /* should not happen */

4
net/core/rtnetlink.c
View File

@ -875,9 +875,9 @@ static void set_operstate(struct net_device *dev, unsigned char transition)
break;
}
if (dev->operstate != operstate) {
if (READ_ONCE(dev->operstate) != operstate) {
write_lock(&dev_base_lock);
dev->operstate = operstate;
WRITE_ONCE(dev->operstate, operstate);
write_unlock(&dev_base_lock);
netdev_state_change(dev);
}

10
net/hsr/hsr_device.c
View File

@ -31,8 +31,8 @@ static bool is_slave_up(struct net_device *dev)
static void __hsr_set_operstate(struct net_device *dev, int transition)
{
write_lock(&dev_base_lock);
if (dev->operstate != transition) {
dev->operstate = transition;
if (READ_ONCE(dev->operstate) != transition) {
WRITE_ONCE(dev->operstate, transition);
write_unlock(&dev_base_lock);
netdev_state_change(dev);
} else {
@ -78,14 +78,14 @@ static void hsr_check_announce(struct net_device *hsr_dev,
hsr = netdev_priv(hsr_dev);
if (hsr_dev->operstate == IF_OPER_UP && old_operstate != IF_OPER_UP) {
if (READ_ONCE(hsr_dev->operstate) == IF_OPER_UP && old_operstate != IF_OPER_UP) {
/* Went up */
hsr->announce_count = 0;
mod_timer(&hsr->announce_timer,
jiffies + msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL));
}
if (hsr_dev->operstate != IF_OPER_UP && old_operstate == IF_OPER_UP)
if (READ_ONCE(hsr_dev->operstate) != IF_OPER_UP && old_operstate == IF_OPER_UP)
/* Went down */
del_timer(&hsr->announce_timer);
}
@ -100,7 +100,7 @@ void hsr_check_carrier_and_operstate(struct hsr_priv *hsr)
/* netif_stacked_transfer_operstate() cannot be used here since
* it doesn't set IF_OPER_LOWERLAYERDOWN (?)
*/
old_operstate = master->dev->operstate;
old_operstate = READ_ONCE(master->dev->operstate);
has_carrier = hsr_check_carrier(master);
hsr_set_operstate(master, has_carrier);
hsr_check_announce(master->dev, old_operstate);

2
net/ipv6/addrconf.c
View File

@ -6015,7 +6015,7 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
(dev->ifindex != dev_get_iflink(dev) &&
nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))) ||
nla_put_u8(skb, IFLA_OPERSTATE,
netif_running(dev) ? dev->operstate : IF_OPER_DOWN))
netif_running(dev) ? READ_ONCE(dev->operstate) : IF_OPER_DOWN))
goto nla_put_failure;
protoinfo = nla_nest_start_noflag(skb, IFLA_PROTINFO);
if (!protoinfo)