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net-sysfs: convert netdev_show() to RCU

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Make clear dev_isalive() can be called with RCU protection.

Then convert netdev_show() to RCU, to remove dev_base_lock
dependency.

Also add RCU to broadcast_show().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2024-02-13 06:32:37 +00:00
committed by David S. Miller
parent 4d42b37def
commit 12692e3df2
1 changed files with 10 additions and 7 deletions
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17
net/core/net-sysfs.c
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@@ -34,10 +34,10 @@ static const char fmt_dec[] = "%d\n";
static const char fmt_ulong[] = "%lu\n"; static const char fmt_ulong[] = "%lu\n";
static const char fmt_u64[] = "%llu\n"; static const char fmt_u64[] = "%llu\n";
/* Caller holds RTNL or dev_base_lock */ /* Caller holds RTNL, RCU or dev_base_lock */
static inline int dev_isalive(const struct net_device *dev) static inline int dev_isalive(const struct net_device *dev)
{ {
return dev->reg_state <= NETREG_REGISTERED; return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED;
} }
/* use same locking rules as GIF* ioctl's */ /* use same locking rules as GIF* ioctl's */
@@ -48,10 +48,10 @@ static ssize_t netdev_show(const struct device *dev,
struct net_device *ndev = to_net_dev(dev); struct net_device *ndev = to_net_dev(dev);
ssize_t ret = -EINVAL; ssize_t ret = -EINVAL;
read_lock(&dev_base_lock); rcu_read_lock();
if (dev_isalive(ndev)) if (dev_isalive(ndev))
ret = (*format)(ndev, buf); ret = (*format)(ndev, buf);
read_unlock(&dev_base_lock); rcu_read_unlock();
return ret; return ret;
} }
@@ -60,7 +60,7 @@ static ssize_t netdev_show(const struct device *dev,
#define NETDEVICE_SHOW(field, format_string) \ #define NETDEVICE_SHOW(field, format_string) \
static ssize_t format_##field(const struct net_device *dev, char *buf) \ static ssize_t format_##field(const struct net_device *dev, char *buf) \
{ \ { \
return sysfs_emit(buf, format_string, dev->field); \ return sysfs_emit(buf, format_string, READ_ONCE(dev->field)); \
} \ } \
static ssize_t field##_show(struct device *dev, \ static ssize_t field##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \ struct device_attribute *attr, char *buf) \
@@ -161,10 +161,13 @@ static ssize_t broadcast_show(struct device *dev,
struct device_attribute *attr, char *buf) struct device_attribute *attr, char *buf)
{ {
struct net_device *ndev = to_net_dev(dev); struct net_device *ndev = to_net_dev(dev);
int ret = -EINVAL;
rcu_read_lock();
if (dev_isalive(ndev)) if (dev_isalive(ndev))
return sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len); ret = sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len);
return -EINVAL; rcu_read_unlock();
return ret;
} }
static DEVICE_ATTR_RO(broadcast); static DEVICE_ATTR_RO(broadcast);