kernel/include/net/pkt_sched.h, branch linux-5.2.y

net/sched: fix race between deactivation and dequeue for NOLOCK qdisc

2019-09-21T05:18:10Z

[ Upstream commit d518d2ed8640c1cbbbb6f63939e3e65471817367 ] The test implemented by some_qdisc_is_busy() is somewhat loosy for NOLOCK qdisc, as we may hit the following scenario: CPU1 CPU2 // in net_tx_action() clear_bit(__QDISC_STATE_SCHED...); // in some_qdisc_is_busy() val = (qdisc_is_running(q) || test_bit(__QDISC_STATE_SCHED, &q->state)); // here val is 0 but... qdisc_run(q) // ... CPU1 is going to run the qdisc next As a conseguence qdisc_run() in net_tx_action() can race with qdisc_reset() in dev_qdisc_reset(). Such race is not possible for !NOLOCK qdisc as both the above bit operations are under the root qdisc lock(). After commit 021a17ed796b ("pfifo_fast: drop unneeded additional lock on dequeue") the race can cause use after free and/or null ptr dereference, but the root cause is likely older. This patch addresses the issue explicitly checking for deactivation under the seqlock for NOLOCK qdisc, so that the qdisc_run() in the critical scenario becomes a no-op. Note that the enqueue() op can still execute concurrently with dev_qdisc_reset(), but that is safe due to the skb_array() locking, and we can't avoid that for NOLOCK qdiscs. Fixes: 021a17ed796b ("pfifo_fast: drop unneeded additional lock on dequeue") Reported-by: Li Shuang Reported-and-tested-by: Davide Caratti Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: extend Qdisc with rcu

2018-09-26T03:17:35Z

Currently, Qdisc API functions assume that users have rtnl lock taken. To implement rtnl unlocked classifiers update interface, Qdisc API must be extended with functions that do not require rtnl lock. Extend Qdisc structure with rcu. Implement special version of put function qdisc_put_unlocked() that is called without rtnl lock taken. This function only takes rtnl lock if Qdisc reference counter reached zero and is intended to be used as optimization. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net/sched: Add HW offloading capability to ETF

2018-07-04T13:30:27Z

Add infra so etf qdisc supports HW offload of time-based transmission. For hw offload, the time sorted list is still used, so packets are dequeued always in order of txtime. Example: $ tc qdisc replace dev enp2s0 parent root handle 100 mqprio num_tc 3 \ map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0 $ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 100000 \ clockid CLOCK_REALTIME In this example, the Qdisc will use HW offload for the control of the transmission time through the network adapter. The hrtimer used for packets scheduling inside the qdisc will use the clockid CLOCK_REALTIME as reference and packets leave the Qdisc "delta" (100000) nanoseconds before their transmission time. Because this will be using HW offload and since dynamic clocks are not supported by the hrtimer, the system clock and the PHC clock must be synchronized for this mode to behave as expected. Signed-off-by: Jesus Sanchez-Palencia Signed-off-by: David S. Miller

net/sched: Allow creating a Qdisc watchdog with other clocks

2018-07-04T13:30:27Z

This adds 'qdisc_watchdog_init_clockid()' that allows a clockid to be passed, this allows other time references to be used when scheduling the Qdisc to run. Signed-off-by: Vinicius Costa Gomes Signed-off-by: David S. Miller

net: remove prototype of qdisc_lookup_class()

2018-01-16T19:56:54Z

Looks like qdisc_lookup_class() never existed in the tree in the git era. Remove the prototype from the header. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller

net: sch: api: add extack support in qdisc_create_dflt

2017-12-21T17:32:51Z

This patch adds extack support for the function qdisc_create_dflt which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_create_dflt failed. The function qdisc_create_dflt will also call an init callback which can fail by any per-qdisc specific handling. Cc: David Ahern Acked-by: Jamal Hadi Salim Signed-off-by: Alexander Aring Signed-off-by: David S. Miller

net: sch: api: add extack support in qdisc_get_rtab

2017-12-21T17:32:50Z

This patch adds extack support for the function qdisc_get_rtab which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_get_rtab failed. Cc: David Ahern Acked-by: Jamal Hadi Salim Signed-off-by: Alexander Aring Signed-off-by: David S. Miller

net: sched: remove remaining uses for qdisc_qlen in xmit path

2017-12-08T18:32:25Z

sch_direct_xmit() uses qdisc_qlen as a return value but all call sites of the routine only check if it is zero or not. Simplify the logic so that we don't need to return an actual queue length value. This introduces a case now where sch_direct_xmit would have returned a qlen of zero but now it returns true. However in this case all call sites of sch_direct_xmit will implement a dequeue() and get a null skb and abort. This trades tracking qlen in the hotpath for an extra dequeue operation. Overall this seems to be good for performance. Signed-off-by: John Fastabend Signed-off-by: David S. Miller

net: sched: cleanup qdisc_run and __qdisc_run semantics

2017-12-08T18:32:25Z

Currently __qdisc_run calls qdisc_run_end() but does not call qdisc_run_begin(). This makes it hard to track pairs of qdisc_run_{begin,end} across function calls. To simplify reading these code paths this patch moves begin/end calls into qdisc_run(). Signed-off-by: John Fastabend Signed-off-by: David S. Miller

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

2017-11-04T00:26:51Z

Files removed in 'net-next' had their license header updated in 'net'. We take the remove from 'net-next'. Signed-off-by: David S. Miller