[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>

1 files changed, 8 insertions, 7 deletions

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.