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>
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@ -68,7 +68,7 @@ extern struct neigh_table dn_neigh_table;
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*/
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*/
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__le16 decnet_address = 0;
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__le16 decnet_address = 0;
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static DEFINE_RWLOCK(dndev_lock);
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static DEFINE_SPINLOCK(dndev_lock);
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static struct net_device *decnet_default_device;
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static struct net_device *decnet_default_device;
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static BLOCKING_NOTIFIER_HEAD(dnaddr_chain);
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static BLOCKING_NOTIFIER_HEAD(dnaddr_chain);
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@ -557,7 +557,8 @@ rarok:
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struct net_device *dn_dev_get_default(void)
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struct net_device *dn_dev_get_default(void)
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{
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{
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struct net_device *dev;
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struct net_device *dev;
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read_lock(&dndev_lock);
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spin_lock(&dndev_lock);
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dev = decnet_default_device;
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dev = decnet_default_device;
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if (dev) {
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if (dev) {
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if (dev->dn_ptr)
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if (dev->dn_ptr)
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@ -565,7 +566,8 @@ struct net_device *dn_dev_get_default(void)
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else
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else
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dev = NULL;
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dev = NULL;
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}
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}
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read_unlock(&dndev_lock);
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spin_unlock(&dndev_lock);
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return dev;
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return dev;
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}
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}
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@ -575,13 +577,15 @@ int dn_dev_set_default(struct net_device *dev, int force)
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int rv = -EBUSY;
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int rv = -EBUSY;
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if (!dev->dn_ptr)
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if (!dev->dn_ptr)
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return -ENODEV;
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return -ENODEV;
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write_lock(&dndev_lock);
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spin_lock(&dndev_lock);
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if (force || decnet_default_device == NULL) {
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if (force || decnet_default_device == NULL) {
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old = decnet_default_device;
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old = decnet_default_device;
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decnet_default_device = dev;
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decnet_default_device = dev;
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rv = 0;
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rv = 0;
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}
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}
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write_unlock(&dndev_lock);
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spin_unlock(&dndev_lock);
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if (old)
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if (old)
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dev_put(old);
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dev_put(old);
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return rv;
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return rv;
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@ -589,13 +593,14 @@ int dn_dev_set_default(struct net_device *dev, int force)
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static void dn_dev_check_default(struct net_device *dev)
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static void dn_dev_check_default(struct net_device *dev)
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{
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{
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write_lock(&dndev_lock);
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spin_lock(&dndev_lock);
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if (dev == decnet_default_device) {
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if (dev == decnet_default_device) {
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decnet_default_device = NULL;
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decnet_default_device = NULL;
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} else {
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} else {
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dev = NULL;
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dev = NULL;
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}
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}
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write_unlock(&dndev_lock);
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spin_unlock(&dndev_lock);
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if (dev)
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if (dev)
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dev_put(dev);
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dev_put(dev);
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}
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}
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