net: devnet_rename_seq should be a seqcount
Using a seqlock for devnet_rename_seq is not a good idea,
as device_rename() can sleep.
As we hold RTNL, we dont need a protection for writers,
and only need a seqcount so that readers can catch a change done
by a writer.
Bug added in commit c91f6df2db4972d3 (sockopt: Change getsockopt() of
SO_BINDTODEVICE to return an interface name)
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index d0cbc93..515473e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -203,7 +203,7 @@
DEFINE_RWLOCK(dev_base_lock);
EXPORT_SYMBOL(dev_base_lock);
-DEFINE_SEQLOCK(devnet_rename_seq);
+seqcount_t devnet_rename_seq;
static inline void dev_base_seq_inc(struct net *net)
{
@@ -1093,10 +1093,10 @@
if (dev->flags & IFF_UP)
return -EBUSY;
- write_seqlock(&devnet_rename_seq);
+ write_seqcount_begin(&devnet_rename_seq);
if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
- write_sequnlock(&devnet_rename_seq);
+ write_seqcount_end(&devnet_rename_seq);
return 0;
}
@@ -1104,7 +1104,7 @@
err = dev_get_valid_name(net, dev, newname);
if (err < 0) {
- write_sequnlock(&devnet_rename_seq);
+ write_seqcount_end(&devnet_rename_seq);
return err;
}
@@ -1112,11 +1112,11 @@
ret = device_rename(&dev->dev, dev->name);
if (ret) {
memcpy(dev->name, oldname, IFNAMSIZ);
- write_sequnlock(&devnet_rename_seq);
+ write_seqcount_end(&devnet_rename_seq);
return ret;
}
- write_sequnlock(&devnet_rename_seq);
+ write_seqcount_end(&devnet_rename_seq);
write_lock_bh(&dev_base_lock);
hlist_del_rcu(&dev->name_hlist);
@@ -1135,7 +1135,7 @@
/* err >= 0 after dev_alloc_name() or stores the first errno */
if (err >= 0) {
err = ret;
- write_seqlock(&devnet_rename_seq);
+ write_seqcount_begin(&devnet_rename_seq);
memcpy(dev->name, oldname, IFNAMSIZ);
goto rollback;
} else {
@@ -4180,7 +4180,7 @@
return -EFAULT;
retry:
- seq = read_seqbegin(&devnet_rename_seq);
+ seq = read_seqcount_begin(&devnet_rename_seq);
rcu_read_lock();
dev = dev_get_by_index_rcu(net, ifr.ifr_ifindex);
if (!dev) {
@@ -4190,7 +4190,7 @@
strcpy(ifr.ifr_name, dev->name);
rcu_read_unlock();
- if (read_seqretry(&devnet_rename_seq, seq))
+ if (read_seqcount_retry(&devnet_rename_seq, seq))
goto retry;
if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))