diff options
| author | stephen hemminger <shemminger@vyatta.com> | 2009-11-11 07:40:36 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-11-11 19:22:18 -0800 |
| commit | e5c140a340c4796054b0f6e9035e1faa7edfa6d6 (patch) | |
| tree | ca150ab28a91eba36838ffc1519840fac705aa82 /net/decnet/dn_dev.c | |
| parent | 41bdecf17e6dba92256c65972ec79a482d978be5 (diff) | |
| download | lwn-e5c140a340c4796054b0f6e9035e1faa7edfa6d6.tar.gz lwn-e5c140a340c4796054b0f6e9035e1faa7edfa6d6.zip | |
decnet: convert dndev_lock to spinlock
There is no reason for this lock to be reader/writer since
the reader only has lock held for a very brief period.
The overhead of read_lock is more expensive than spinlock.
Compile tested only, I am not a decnet user.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/decnet/dn_dev.c')
| -rw-r--r-- | net/decnet/dn_dev.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c index 5790d660bc7d..6c916e2b8a84 100644 --- a/net/decnet/dn_dev.c +++ b/net/decnet/dn_dev.c @@ -68,7 +68,7 @@ extern struct neigh_table dn_neigh_table; */ __le16 decnet_address = 0; -static DEFINE_RWLOCK(dndev_lock); +static DEFINE_SPINLOCK(dndev_lock); static struct net_device *decnet_default_device; static BLOCKING_NOTIFIER_HEAD(dnaddr_chain); @@ -557,7 +557,8 @@ rarok: struct net_device *dn_dev_get_default(void) { struct net_device *dev; - read_lock(&dndev_lock); + + spin_lock(&dndev_lock); dev = decnet_default_device; if (dev) { if (dev->dn_ptr) @@ -565,7 +566,8 @@ struct net_device *dn_dev_get_default(void) else dev = NULL; } - read_unlock(&dndev_lock); + spin_unlock(&dndev_lock); + return dev; } @@ -575,13 +577,15 @@ int dn_dev_set_default(struct net_device *dev, int force) int rv = -EBUSY; if (!dev->dn_ptr) return -ENODEV; - write_lock(&dndev_lock); + + spin_lock(&dndev_lock); if (force || decnet_default_device == NULL) { old = decnet_default_device; decnet_default_device = dev; rv = 0; } - write_unlock(&dndev_lock); + spin_unlock(&dndev_lock); + if (old) dev_put(old); return rv; @@ -589,13 +593,14 @@ int dn_dev_set_default(struct net_device *dev, int force) static void dn_dev_check_default(struct net_device *dev) { - write_lock(&dndev_lock); + spin_lock(&dndev_lock); if (dev == decnet_default_device) { decnet_default_device = NULL; } else { dev = NULL; } - write_unlock(&dndev_lock); + spin_unlock(&dndev_lock); + if (dev) dev_put(dev); } |