From: Stephen Hemminger Date: Sun, 8 Jul 2007 05:59:14 +0000 (-0700) Subject: [NET]: netdevice locking assumptions documentation X-Git-Tag: v2.6.23-rc1~1109^2~36 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=1722933323b70f44b0548131604f1f3454c2aa8f;p=linux-2.6-omap-h63xx.git [NET]: netdevice locking assumptions documentation Update the documentation about locking assumptions. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index ce1361f9524..a6cab674b67 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -20,7 +20,6 @@ private data which gets freed when the network device is freed. If separately allocated data is attached to the network device (dev->priv) then it is up to the module exit handler to free that. - struct net_device synchronization rules ======================================= dev->open: @@ -43,16 +42,17 @@ dev->get_stats: dev->hard_start_xmit: Synchronization: netif_tx_lock spinlock. + When the driver sets NETIF_F_LLTX in dev->features this will be called without holding netif_tx_lock. In this case the driver has to lock by itself when needed. It is recommended to use a try lock - for this and return -1 when the spin lock fails. + for this and return NETDEV_TX_LOCKED when the spin lock fails. The locking there should also properly protect against - set_multicast_list - Context: Process with BHs disabled or BH (timer). - Notes: netif_queue_stopped() is guaranteed false - Interrupts must be enabled when calling hard_start_xmit. - (Interrupts must also be enabled when enabling the BH handler.) + set_multicast_list. + + Context: Process with BHs disabled or BH (timer), + will be called with interrupts disabled by netconsole. + Return codes: o NETDEV_TX_OK everything ok. o NETDEV_TX_BUSY Cannot transmit packet, try later @@ -74,4 +74,5 @@ dev->poll: Synchronization: __LINK_STATE_RX_SCHED bit in dev->state. See dev_close code and comments in net/core/dev.c for more info. Context: softirq + will be called with interrupts disabled by netconsole.