path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2012-04-06 10:37:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-06 10:37:38 -0700
commit23f347ef63aa36b5a001b6791f657cd0e2a04de3 (patch)
treece06ebdccd16b99265b3e74f8e9b7bd1e29cf465 /Documentation
parent314489bd4c7780fde6a069783d5128f6cef52919 (diff)
parent110c43304db6f06490961529536c362d9ac5732f (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking updates from David Miller: 1) Fix inaccuracies in network driver interface documentation, from Ben Hutchings. 2) Fix handling of negative offsets in BPF JITs, from Jan Seiffert. 3) Compile warning, locking, and refcounting fixes in netfilter's xt_CT, from Pablo Neira Ayuso. 4) phonet sendmsg needs to validate user length just like any other datagram protocol, fix from Sasha Levin. 5) Ipv6 multicast code uses wrong loop index, from RongQing Li. 6) Link handling and firmware fixes in bnx2x driver from Yaniv Rosner and Yuval Mintz. 7) mlx4 erroneously allocates 4 pages at a time, regardless of page size, fix from Thadeu Lima de Souza Cascardo. 8) SCTP socket option wasn't extended in a backwards compatible way, fix from Thomas Graf. 9) Add missing address change event emissions to bonding, from Shlomo Pongratz. 10) /proc/net/dev regressed because it uses a private offset to track where we are in the hash table, but this doesn't track the offset pullback that the seq_file code does resulting in some entries being missed in large dumps. Fix from Eric Dumazet. 11) do_tcp_sendpage() unloads the send queue way too fast, because it invokes tcp_push() when it shouldn't. Let the natural sequence generated by the splice paths, and the assosciated MSG_MORE settings, guide the tcp_push() calls. Otherwise what goes out of TCP is spaghetti and doesn't batch effectively into GSO/TSO clusters. From Eric Dumazet. 12) Once we put a SKB into either the netlink receiver's queue or a socket error queue, it can be consumed and freed up, therefore we cannot touch it after queueing it like that. Fixes from Eric Dumazet. 13) PPP has this annoying behavior in that for every transmit call it immediately stops the TX queue, then calls down into the next layer to transmit the PPP frame. But if that next layer can take it immediately, it just un-stops the TX queue right before returning from the transmit method. Besides being useless work, it makes several facilities unusable, in particular things like the equalizers. Well behaved devices should only stop the TX queue when they really are full, and in PPP's case when it gets backlogged to the downstream device. David Woodhouse therefore fixed PPP to not stop the TX queue until it's downstream can't take data any more. 14) IFF_UNICAST_FLT got accidently lost in some recent stmmac driver changes, re-add. From Marc Kleine-Budde. 15) Fix link flaps in ixgbe, from Eric W. Multanen. 16) Descriptor writeback fixes in e1000e from Matthew Vick. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits) net: fix a race in sock_queue_err_skb() netlink: fix races after skb queueing doc, net: Update ndo_start_xmit return type and values doc, net: Remove instruction to set net_device::trans_start doc, net: Update netdev operation names doc, net: Update documentation of synchronisation for TX multiqueue doc, net: Remove obsolete reference to dev->poll ethtool: Remove exception to the requirement of holding RTNL lock MAINTAINERS: update for Marvell Ethernet drivers bonding: properly unset current_arp_slave on slave link up phonet: Check input from user before allocating tcp: tcp_sendpages() should call tcp_push() once ipv6: fix array index in ip6_mc_add_src() mlx4: allocate just enough pages instead of always 4 pages stmmac: re-add IFF_UNICAST_FLT for dwmac1000 bnx2x: Clear MDC/MDIO warning message bnx2x: Fix BCM57711+BCM84823 link issue bnx2x: Clear BCM84833 LED after fan failure bnx2x: Fix BCM84833 PHY FW version presentation bnx2x: Fix link issue for BCM8727 boards. ...
Diffstat (limited to 'Documentation')
3 files changed, 29 insertions, 38 deletions
diff --git a/Documentation/networking/driver.txt b/Documentation/networking/driver.txt
index 03283daa64fe..da59e2884130 100644
--- a/Documentation/networking/driver.txt
+++ b/Documentation/networking/driver.txt
@@ -2,16 +2,16 @@ Document about softnet driver issues
Transmit path guidelines:
-1) The hard_start_xmit method must never return '1' under any
- normal circumstances. It is considered a hard error unless
+1) The ndo_start_xmit method must not return NETDEV_TX_BUSY under
+ any normal circumstances. It is considered a hard error unless
there is no way your device can tell ahead of time when it's
transmit function will become busy.
Instead it must maintain the queue properly. For example,
for a driver implementing scatter-gather this means:
- static int drv_hard_start_xmit(struct sk_buff *skb,
- struct net_device *dev)
+ static netdev_tx_t drv_hard_start_xmit(struct sk_buff *skb,
+ struct net_device *dev)
struct drv *dp = netdev_priv(dev);
@@ -23,7 +23,7 @@ Transmit path guidelines:
printk(KERN_ERR PFX "%s: BUG! Tx Ring full when queue awake!\n",
- return 1;
+ return NETDEV_TX_BUSY;
... queue packet to card ...
@@ -35,6 +35,7 @@ Transmit path guidelines:
+ return NETDEV_TX_OK;
And then at the end of your TX reclamation event handling:
@@ -58,15 +59,12 @@ Transmit path guidelines:
-2) Do not forget to update netdev->trans_start to jiffies after
- each new tx packet is given to the hardware.
-3) A hard_start_xmit method must not modify the shared parts of a
+2) An ndo_start_xmit method must not modify the shared parts of a
cloned SKB.
-4) Do not forget that once you return 0 from your hard_start_xmit
- method, it is your driver's responsibility to free up the SKB
- and in some finite amount of time.
+3) Do not forget that once you return NETDEV_TX_OK from your
+ ndo_start_xmit method, it is your driver's responsibility to free
+ up the SKB and in some finite amount of time.
For example, this means that it is not allowed for your TX
mitigation scheme to let TX packets "hang out" in the TX
@@ -74,8 +72,9 @@ Transmit path guidelines:
This error can deadlock sockets waiting for send buffer room
to be freed up.
- If you return 1 from the hard_start_xmit method, you must not keep
- any reference to that SKB and you must not attempt to free it up.
+ If you return NETDEV_TX_BUSY from the ndo_start_xmit method, you
+ must not keep any reference to that SKB and you must not attempt
+ to free it up.
Probing guidelines:
@@ -85,10 +84,10 @@ Probing guidelines:
Close/stop guidelines:
-1) After the dev->stop routine has been called, the hardware must
+1) After the ndo_stop routine has been called, the hardware must
not receive or transmit any data. All in flight packets must
be aborted. If necessary, poll or wait for completion of
any reset commands.
-2) The dev->stop routine will be called by unregister_netdevice
+2) The ndo_stop routine will be called by unregister_netdevice
if device is still UP.
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index ad3e80e17b4f..bd80ba5847d2 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -604,15 +604,8 @@ IP Variables:
ip_local_port_range - 2 INTEGERS
Defines the local port range that is used by TCP and UDP to
choose the local port. The first number is the first, the
- second the last local port number. Default value depends on
- amount of memory available on the system:
- > 128Mb 32768-61000
- < 128Mb 1024-4999 or even less.
- This number defines number of active connections, which this
- system can issue simultaneously to systems not supporting
- TCP extensions (timestamps). With tcp_tw_recycle enabled
- (i.e. by default) range 1024-4999 is enough to issue up to
- 2000 connections per second to systems supporting timestamps.
+ second the last local port number. The default values are
+ 32768 and 61000 respectively.
ip_local_reserved_ports - list of comma separated ranges
Specify the ports which are reserved for known third-party
diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt
index 89358341682a..c7ecc7080494 100644
--- a/Documentation/networking/netdevices.txt
+++ b/Documentation/networking/netdevices.txt
@@ -47,26 +47,25 @@ packets is preferred.
struct net_device synchronization rules
Synchronization: rtnl_lock() semaphore.
Context: process
Synchronization: rtnl_lock() semaphore.
Context: process
- Note1: netif_running() is guaranteed false
- Note2: dev->poll() is guaranteed to be stopped
+ Note: netif_running() is guaranteed false
Synchronization: rtnl_lock() semaphore.
Context: process
Synchronization: dev_base_lock rwlock.
Context: nominally process, but don't sleep inside an rwlock
- Synchronization: netif_tx_lock spinlock.
+ 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
@@ -87,20 +86,20 @@ dev->hard_start_xmit:
o NETDEV_TX_LOCKED Locking failed, please retry quickly.
Only valid when NETIF_F_LLTX is set.
- Synchronization: netif_tx_lock spinlock.
+ Synchronization: netif_tx_lock spinlock; all TX queues frozen.
Context: BHs disabled
Notes: netif_queue_stopped() is guaranteed true
- Synchronization: netif_tx_lock spinlock.
+ Synchronization: netif_addr_lock spinlock.
Context: BHs disabled
struct napi_struct synchronization rules
Synchronization: NAPI_STATE_SCHED bit in napi->state. Device
- driver's dev->close method will invoke napi_disable() on
+ driver's ndo_stop method will invoke napi_disable() on
all NAPI instances which will do a sleeping poll on the
NAPI_STATE_SCHED napi->state bit, waiting for all pending
NAPI activity to cease.

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