kernel/include/linux/netdevice.h, branch linux-4.11.y

net: ipv6: Release route when device is unregistering

2017-07-05T12:41:35Z

[ Upstream commit 8397ed36b7c585f8d3e06c431f4137309124f78f ] Roopa reported attempts to delete a bond device that is referenced in a multipath route is hanging: $ ifdown bond2 # ifupdown2 command that deletes virtual devices unregister_netdevice: waiting for bond2 to become free. Usage count = 2 Steps to reproduce: echo 1 > /proc/sys/net/ipv6/conf/all/ignore_routes_with_linkdown ip link add dev bond12 type bond ip link add dev bond13 type bond ip addr add 2001:db8:2::0/64 dev bond12 ip addr add 2001:db8:3::0/64 dev bond13 ip route add 2001:db8:33::0/64 nexthop via 2001:db8:2::2 nexthop via 2001:db8:3::2 ip link del dev bond12 ip link del dev bond13 The root cause is the recent change to keep routes on a linkdown. Update the check to detect when the device is unregistering and release the route for that case. Fixes: a1a22c12060e4 ("net: ipv6: Keep nexthop of multipath route on admin down") Reported-by: Roopa Prabhu Signed-off-by: David Ahern Acked-by: Roopa Prabhu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: Fix inconsistent teardown and release of private netdev state.

2017-07-05T12:41:34Z

[ Upstream commit cf124db566e6b036b8bcbe8decbed740bdfac8c6 ] Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: solve a NAPI race

2017-03-01T17:50:58Z

While playing with mlx4 hardware timestamping of RX packets, I found that some packets were received by TCP stack with a ~200 ms delay... Since the timestamp was provided by the NIC, and my probe was added in tcp_v4_rcv() while in BH handler, I was confident it was not a sender issue, or a drop in the network. This would happen with a very low probability, but hurting RPC workloads. A NAPI driver normally arms the IRQ after the napi_complete_done(), after NAPI_STATE_SCHED is cleared, so that the hard irq handler can grab it. Problem is that if another point in the stack grabs NAPI_STATE_SCHED bit while IRQ are not disabled, we might have later an IRQ firing and finding this bit set, right before napi_complete_done() clears it. This can happen with busy polling users, or if gro_flush_timeout is used. But some other uses of napi_schedule() in drivers can cause this as well. thread 1 thread 2 (could be on same cpu, or not) // busy polling or napi_watchdog() napi_schedule(); ... napi->poll() device polling: read 2 packets from ring buffer Additional 3rd packet is available. device hard irq // does nothing because NAPI_STATE_SCHED bit is owned by thread 1 napi_schedule(); napi_complete_done(napi, 2); rearm_irq(); Note that rearm_irq() will not force the device to send an additional IRQ for the packet it already signaled (3rd packet in my example) This patch adds a new NAPI_STATE_MISSED bit, that napi_schedule_prep() can set if it could not grab NAPI_STATE_SCHED Then napi_complete_done() properly reschedules the napi to make sure we do not miss something. Since we manipulate multiple bits at once, use cmpxchg() like in sk_busy_loop() to provide proper transactions. In v2, I changed napi_watchdog() to use a relaxed variant of napi_schedule_prep() : No need to set NAPI_STATE_MISSED from this point. In v3, I added more details in the changelog and clears NAPI_STATE_MISSED in busy_poll_stop() In v4, I added the ideas given by Alexander Duyck in v3 review Signed-off-by: Eric Dumazet Cc: Alexander Duyck Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

2017-02-17T02:25:49Z

Steffen Klassert says: ==================== pull request (net-next): ipsec-next 2017-02-16 1) Make struct xfrm_input_afinfo const, nothing writes to it. From Florian Westphal. 2) Remove all places that write to the afinfo policy backend and make the struct const then. From Florian Westphal. 3) Prepare for packet consuming gro callbacks and add ESP GRO handlers. ESP packets can be decapsulated at the GRO layer then. It saves a round through the stack for each ESP packet. Please note that this has a merge coflict between commit 63fca65d0863 ("net: add confirm_neigh method to dst_ops") from net-next and 3d7d25a68ea5 ("xfrm: policy: remove garbage_collect callback") a2817d8b279b ("xfrm: policy: remove family field") from ipsec-next. The conflict can be solved as it is done in linux-next. Please pull or let me know if there are problems. ==================== Signed-off-by: David S. Miller

net: Prepare gro for packet consuming gro callbacks

2017-02-15T08:39:44Z

The upcomming IPsec ESP gro callbacks will consume the skb, so prepare for that. Signed-off-by: Steffen Klassert

net: Add a skb_gro_flush_final helper.

2017-02-15T08:39:39Z

Add a skb_gro_flush_final helper to prepare for consuming skbs in call_gro_receive. We will extend this helper to not touch the skb if the skb is consumed by a gro callback with a followup patch. We need this to handle the upcomming IPsec ESP callbacks as they reinject the skb to the napi_gro_receive asynchronous. The handler is used in all gro_receive functions that can call the ESP gro handlers. Signed-off-by: Steffen Klassert

net: make net_device members garp_port and mrp_port conditional

2017-02-14T03:23:39Z

garp_port is only used in net/802/garp.c which is only compiled with CONFIG_GARP enabled. Same goes for mrp_port which is only used in net/802/mrp.c with CONFIG_MRP enabled. Only include the two members in struct net_device if their respective CONFIG_* is enabled. This saves a few bytes in struct net_device in case CONFIG_GARP or CONFIG_MRP are not enabled. Signed-off-by: Tobias Klauser Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2017-02-11T07:31:11Z

net: introduce device min_header_len

2017-02-08T18:56:37Z

The stack must not pass packets to device drivers that are shorter than the minimum link layer header length. Previously, packet sockets would drop packets smaller than or equal to dev->hard_header_len, but this has false positives. Zero length payload is used over Ethernet. Other link layer protocols support variable length headers. Support for validation of these protocols removed the min length check for all protocols. Introduce an explicit dev->min_header_len parameter and drop all packets below this value. Initially, set it to non-zero only for Ethernet and loopback. Other protocols can follow in a patch to net-next. Fixes: 9ed988cd5915 ("packet: validate variable length ll headers") Reported-by: Sowmini Varadhan Signed-off-by: Willem de Bruijn Acked-by: Eric Dumazet Acked-by: Sowmini Varadhan Signed-off-by: David S. Miller

net: remove ndo_neigh_{construct, destroy} from stacked devices

2017-02-06T16:25:57Z

In commit 18bfb924f000 ("net: introduce default neigh_construct/destroy ndo calls for L2 upper devices") we added these ndos to stacked devices such as team and bond, so that calls will be propagated to mlxsw. However, previous commit removed the reliance on these ndos and no new users of these ndos have appeared since above mentioned commit. We can therefore safely remove this dead code. Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller