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[NET]: netdevice locking assumptions documentation 

Update the documentation about locking assumptions.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger 2007-07-07 22:59:14 -07:00 committed by David S. Miller
parent 963bd949b1
commit 1722933323
1 changed files with 8 additions and 7 deletions
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15
Documentation/networking/netdevices.txt
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@ -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.