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authorFlorian Westphal <fw@strlen.de>2017-10-03 00:50:05 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-04 01:56:01 +0300
commit6c5570016b972d9b1f0f6c2dca9cc0422b1f92bf (patch)
tree2ee918eba58118a7cd86a97ba07fc26c4a743a2d /net/core/net-sysfs.c
parent4d2c0cda07448ea6980f00102dc3964eb25e241c (diff)
downloadlinux-6c5570016b972d9b1f0f6c2dca9cc0422b1f92bf.tar.xz
net: core: decouple ifalias get/set from rtnl lock
Device alias can be set by either rtnetlink (rtnl is held) or sysfs. rtnetlink hold the rtnl mutex, sysfs acquires it for this purpose. Add an extra mutex for it and use rcu to protect concurrent accesses. This allows the sysfs path to not take rtnl and would later allow to not hold it when dumping ifalias. Based on suggestion from Eric Dumazet. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/net-sysfs.c')
-rw-r--r--net/core/net-sysfs.c17
1 files changed, 8 insertions, 9 deletions
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 927a6dcbad96..51d5836d8fb9 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -391,10 +391,7 @@ static ssize_t ifalias_store(struct device *dev, struct device_attribute *attr,
if (len > 0 && buf[len - 1] == '\n')
--count;
- if (!rtnl_trylock())
- return restart_syscall();
ret = dev_set_alias(netdev, buf, count);
- rtnl_unlock();
return ret < 0 ? ret : len;
}
@@ -403,13 +400,12 @@ static ssize_t ifalias_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const struct net_device *netdev = to_net_dev(dev);
+ char tmp[IFALIASZ];
ssize_t ret = 0;
- if (!rtnl_trylock())
- return restart_syscall();
- if (netdev->ifalias)
- ret = sprintf(buf, "%s\n", netdev->ifalias);
- rtnl_unlock();
+ ret = dev_get_alias(netdev, tmp, sizeof(tmp));
+ if (ret > 0)
+ ret = sprintf(buf, "%s\n", tmp);
return ret;
}
static DEVICE_ATTR_RW(ifalias);
@@ -1488,7 +1484,10 @@ static void netdev_release(struct device *d)
BUG_ON(dev->reg_state != NETREG_RELEASED);
- kfree(dev->ifalias);
+ /* no need to wait for rcu grace period:
+ * device is dead and about to be freed.
+ */
+ kfree(rcu_access_pointer(dev->ifalias));
netdev_freemem(dev);
}