diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2007-07-30 17:03:38 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-07-31 02:28:15 -0700 |
| commit | fcc5a03ac42564e9e255c1134dda47442289e466 (patch) | |
| tree | 8be87d6dc1a58b8ccd27de930c17bc1c9c26bac9 /include/linux/notifier.h | |
| parent | aeed9e82cd258b9699eaa6568efefba9cc6d5f01 (diff) | |
[NET]: Allow netdev REGISTER/CHANGENAME events to fail
This patch adds code to allow errors to be passed up from event
handlers of NETDEV_REGISTER and NETDEV_CHANGENAME. It also adds
the notifier_from_errno/notifier_to_errnor helpers to pass the
errno value up to the notifier caller.
If an error is detected when a device is registered, it causes
that operation to fail. A NETDEV_UNREGISTER will be sent to
all event handlers.
Similarly if NETDEV_CHANGENAME fails the original name is restored
and a new NETDEV_CHANGENAME event is sent.
As such all event handlers must be idempotent with respect to
these events.
When an event handler is registered NETDEV_REGISTER events are
sent for all devices currently registered. Should any of them
fail, we will send NETDEV_GOING_DOWN/NETDEV_DOWN/NETDEV_UNREGISTER
events to that handler for the devices which have already been
registered with it. The handler registration itself will fail.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/notifier.h')
| -rw-r--r-- | include/linux/notifier.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/notifier.h b/include/linux/notifier.h index be3f2bb6fcf3..fad7ff17e468 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -157,6 +157,19 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, */ #define NOTIFY_STOP (NOTIFY_OK|NOTIFY_STOP_MASK) +/* Encapsulate (negative) errno value (in particular, NOTIFY_BAD <=> EPERM). */ +static inline int notifier_from_errno(int err) +{ + return NOTIFY_STOP_MASK | (NOTIFY_OK - err); +} + +/* Restore (negative) errno value from notify return value. */ +static inline int notifier_to_errno(int ret) +{ + ret &= ~NOTIFY_STOP_MASK; + return ret > NOTIFY_OK ? NOTIFY_OK - ret : 0; +} + /* * Declared notifiers so far. I can imagine quite a few more chains * over time (eg laptop power reset chains, reboot chain (to clean |