kernel/include/net/sch_generic.h, branch linux-4.16.y

net: sched, fix OOO packets with pfifo_fast

2018-03-26T16:36:23Z

After the qdisc lock was dropped in pfifo_fast we allow multiple enqueue threads and dequeue threads to run in parallel. On the enqueue side the skb bit ooo_okay is used to ensure all related skbs are enqueued in-order. On the dequeue side though there is no similar logic. What we observe is with fewer queues than CPUs it is possible to re-order packets when two instances of __qdisc_run() are running in parallel. Each thread will dequeue a skb and then whichever thread calls the ndo op first will be sent on the wire. This doesn't typically happen because qdisc_run() is usually triggered by the same core that did the enqueue. However, drivers will trigger __netif_schedule() when queues are transitioning from stopped to awake using the netif_tx_wake_* APIs. When this happens netif_schedule() calls qdisc_run() on the same CPU that did the netif_tx_wake_* which is usually done in the interrupt completion context. This CPU is selected with the irq affinity which is unrelated to the enqueue operations. To resolve this we add a RUNNING bit to the qdisc to ensure only a single dequeue per qdisc is running. Enqueue and dequeue operations can still run in parallel and also on multi queue NICs we can still have a dequeue in-flight per qdisc, which is typically per CPU. Fixes: c5ad119fb6c0 ("net: sched: pfifo_fast use skb_array") Reported-by: Jakob Unterwurzacher Signed-off-by: John Fastabend Signed-off-by: David S. Miller

sch_netem: fix skb leak in netem_enqueue()

2018-03-07T16:18:14Z

When we exceed current packets limit and we have more than one segment in the list returned by skb_gso_segment(), netem drops only the first one, skipping the rest, hence kmemleak reports: unreferenced object 0xffff880b5d23b600 (size 1024): comm "softirq", pid 0, jiffies 4384527763 (age 2770.629s) hex dump (first 32 bytes): 00 80 23 5d 0b 88 ff ff 00 00 00 00 00 00 00 00 ..#]............ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000d8a19b9d>] __alloc_skb+0xc9/0x520 [<000000001709b32f>] skb_segment+0x8c8/0x3710 [<00000000c7b9bb88>] tcp_gso_segment+0x331/0x1830 [<00000000c921cba1>] inet_gso_segment+0x476/0x1370 [<000000008b762dd4>] skb_mac_gso_segment+0x1f9/0x510 [<000000002182660a>] __skb_gso_segment+0x1dd/0x620 [<00000000412651b9>] netem_enqueue+0x1536/0x2590 [sch_netem] [<0000000005d3b2a9>] __dev_queue_xmit+0x1167/0x2120 [<00000000fc5f7327>] ip_finish_output2+0x998/0xf00 [<00000000d309e9d3>] ip_output+0x1aa/0x2c0 [<000000007ecbd3a4>] tcp_transmit_skb+0x18db/0x3670 [<0000000042d2a45f>] tcp_write_xmit+0x4d4/0x58c0 [<0000000056a44199>] tcp_tasklet_func+0x3d9/0x540 [<0000000013d06d02>] tasklet_action+0x1ca/0x250 [<00000000fcde0b8b>] __do_softirq+0x1b4/0x5a3 [<00000000e7ed027c>] irq_exit+0x1e2/0x210 Fix it by adding the rest of the segments, if any, to skb 'to_free' list. Add new __qdisc_drop_all() and qdisc_drop_all() functions because they can be useful in the future if we need to drop segmented GSO packets in other places. Fixes: 6071bd1aa13e ("netem: Segment GSO packets on enqueue") Signed-off-by: Alexey Kodanev Acked-by: Neil Horman Signed-off-by: David S. Miller

net_sched: plug in qdisc ops change_tx_queue_len

2018-01-29T17:42:15Z

Introduce a new qdisc ops ->change_tx_queue_len() so that each qdisc could decide how to implement this if it wants. Previously we simply read dev->tx_queue_len, after pfifo_fast switches to skb array, we need this API to resize the skb array when we change dev->tx_queue_len. To avoid handling race conditions with TX BH, we need to deactivate all TX queues before change the value and bring them back after we are done, this also makes implementation easier. Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller

net: sched: propagate extack to cls->destroy callbacks

2018-01-24T21:01:09Z

Propagate extack to cls->destroy callbacks when called from non-error paths. On error paths pass NULL to avoid overwriting the failure message. Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net: sched: cls: add extack support for delete callback

2018-01-19T20:52:51Z

This patch adds extack support for classifier delete callback api. This prepares to handle extack support inside each specific classifier implementation. Cc: David Ahern Signed-off-by: Alexander Aring Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: cls: add extack support for change callback

2018-01-19T20:52:51Z

This patch adds extack support for classifier change callback api. This prepares to handle extack support inside each specific classifier implementation. Cc: David Ahern Signed-off-by: Alexander Aring Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: cls: fix code style issues

2018-01-19T20:52:51Z

This patch changes some code style issues pointed out by checkpatch inside the TC cls subsystem. Signed-off-by: Alexander Aring Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: introduce ingress/egress block index attributes for qdisc

2018-01-17T19:53:57Z

Introduce two new attributes to be used for qdisc creation and dumping. One for ingress block, one for egress block. Introduce a set of ops that qdisc which supports block sharing would implement. Passing block indexes in qdisc change is not supported yet and it is checked and forbidded. In future, these attributes are to be reused for specifying block indexes for classes as well. As of this moment however, it is not supported so a check is in place to forbid it. Suggested-by: Roopa Prabhu Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Acked-by: David Ahern Signed-off-by: David S. Miller

net: sched: keep track of offloaded filters and check tc offload feature

2018-01-17T19:53:57Z

During block bind, we need to check tc offload feature. If it is disabled yet still the block contains offloaded filters, forbid the bind. Also forbid to register callback for a block that already contains offloaded filters, as the play back is not supported now. For keeping track of offloaded filters there is a new counter introduced, alongside with couple of helpers called from cls_* code. These helpers set and clear TCA_CLS_FLAGS_IN_HW flag. Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Acked-by: David Ahern Signed-off-by: David S. Miller

net: sched: remove classid and q fields from tcf_proto

2018-01-17T19:53:56Z

Both are no longer used, so remove them. Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Acked-by: David Ahern Signed-off-by: David S. Miller