kernel.git/drivers/net/xen-netback/interface.c, branch linux-5.8.y

xen-netback: support dynamic unbind/bind

2019-12-26T23:16:26Z

By re-attaching RX, TX, and CTL rings during connect() rather than assuming they are freshly allocated (i.e. assuming the counters are zero), and avoiding forcing state to Closed in netback_remove() it is possible for vif instances to be unbound and re-bound from and to (respectively) a running guest. Dynamic unbind/bind is a highly useful feature for a backend module as it allows it to be unloaded and re-loaded (i.e. updated) without requiring domUs to be halted. This has been tested by running iperf as a server in the test VM and then running a client against it in a continuous loop, whilst also running: while true; do echo vif-$DOMID-$VIF >unbind; echo down; rmmod xen-netback; echo unloaded; modprobe xen-netback; cd $(pwd); brctl addif xenbr0 vif$DOMID.$VIF; ip link set vif$DOMID.$VIF up; echo up; sleep 5; done in dom0 from /sys/bus/xen-backend/drivers/vif to continuously unbind, unload, re-load, re-bind and re-plumb the backend. Clearly a performance drop was seen but no TCP connection resets were observed during this test and moreover a parallel SSH connection into the guest remained perfectly usable throughout. Signed-off-by: Paul Durrant Reviewed-by: Wei Liu Signed-off-by: David S. Miller

xen-netback: avoid race that can lead to NULL pointer dereference

2019-12-15T19:40:15Z

In function xenvif_disconnect_queue(), the value of queue->rx_irq is zeroed *before* queue->task is stopped. Unfortunately that task may call notify_remote_via_irq(queue->rx_irq) and calling that function with a zero value results in a NULL pointer dereference in evtchn_from_irq(). This patch simply re-orders things, stopping all tasks before zero-ing the irq values, thereby avoiding the possibility of the race. Fixes: 2ac061ce97f4 ("xen/netback: cleanup init and deinit code") Signed-off-by: Paul Durrant Acked-by: Wei Liu Signed-off-by: Jakub Kicinski

xen/netback: cleanup init and deinit code

2019-10-22T16:52:04Z

Do some cleanup of the netback init and deinit code: - add an omnipotent queue deinit function usable from xenvif_disconnect_data() and the error path of xenvif_connect_data() - only install the irq handlers after initializing all relevant items (especially the kthreads related to the queue) - there is no need to use get_task_struct() after creating a kthread and using put_task_struct() again after having stopped it. - use kthread_run() instead of kthread_create() to spare the call of wake_up_process(). Signed-off-by: Juergen Gross Reviewed-by: Paul Durrant Signed-off-by: Jakub Kicinski

xen/netback: fix error path of xenvif_connect_data()

2019-10-19T18:43:29Z

xenvif_connect_data() calls module_put() in case of error. This is wrong as there is no related module_get(). Remove the superfluous module_put(). Fixes: 279f438e36c0a7 ("xen-netback: Don't destroy the netdev until the vif is shut down") Cc: # 3.12 Signed-off-by: Juergen Gross Reviewed-by: Paul Durrant Reviewed-by: Wei Liu Signed-off-by: David S. Miller

xen-netback: remove redundant assignment to err

2019-05-31T21:36:48Z

The variable err is assigned with the value -ENOMEM that is never read and it is re-assigned a new value later on. The assignment is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Acked-by: Wei Liu Signed-off-by: David S. Miller

net: remove 'fallback' argument from dev->ndo_select_queue()

2019-03-20T18:18:55Z

After the previous patch, all the callers of ndo_select_queue() provide as a 'fallback' argument netdev_pick_tx. The only exceptions are nested calls to ndo_select_queue(), which pass down the 'fallback' available in the current scope - still netdev_pick_tx. We can drop such argument and replace fallback() invocation with netdev_pick_tx(). This avoids an indirect call per xmit packet in some scenarios (TCP syn, UDP unconnected, XDP generic, pktgen) with device drivers implementing such ndo. It also clean the code a bit. Tested with ixgbe and CONFIG_FCOE=m With pktgen using queue xmit: threads vanilla patched (kpps) (kpps) 1 2334 2428 2 4166 4278 4 7895 8100 v1 -> v2: - rebased after helper's name change Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

xen-netback: don't populate the hash cache on XenBus disconnect

2019-02-28T20:50:37Z

Occasionally, during the disconnection procedure on XenBus which includes hash cache deinitialization there might be some packets still in-flight on other processors. Handling of these packets includes hashing and hash cache population that finally results in hash cache data structure corruption. In order to avoid this we prevent hashing of those packets if there are no queues initialized. In that case RCU protection of queues guards the hash cache as well. Signed-off-by: Igor Druzhinin Reviewed-by: Paul Durrant Signed-off-by: David S. Miller

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

2018-10-04T04:00:17Z

Minor conflict in net/core/rtnetlink.c, David Ahern's bug fix in 'net' overlapped the renaming of a netlink attribute in net-next. Signed-off-by: David S. Miller

net: xen-netback: fix return type of ndo_start_xmit function

2018-09-28T17:25:11Z

The method ndo_start_xmit() is defined as returning an 'netdev_tx_t', which is a typedef for an enum type, so make sure the implementation in this driver has returns 'netdev_tx_t' value, and change the function return type to netdev_tx_t. Found by coccinelle. Signed-off-by: YueHaibing Acked-by: Wei Liu Signed-off-by: David S. Miller

xen-netback: validate queue numbers in xenvif_set_hash_mapping()

2018-09-25T17:39:34Z

Checking them before the grant copy means nothing as to the validity of the incoming request. As we shouldn't make the new data live before having validated it, introduce a second instance of the mapping array. Signed-off-by: Jan Beulich Reviewed-by: Paul Durrant Signed-off-by: David S. Miller