net_sched: prio: insure proper transactional behavior

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Now prio_init() can return -ENOMEM, it also has to make sure
any allocated qdiscs are freed, since the caller (qdisc_create()) wont
call ->destroy() handler for us.

More generally, we want a transactional behavior for "tc qdisc
change ...", so prio_tune() should not make modifications if
any error is returned.

It means that we must validate parameters and allocate missing qdisc(s)
before taking root qdisc lock exactly once, to not leave the prio qdisc
in an intermediate state.

Fixes: cbdf451164 ("net_sched: prio: properly report out of memory errors")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Eric Dumazet 2016-06-13 11:33:32 -07:00 • committed by David S. Miller

parent 0c5ddb51e8

commit 3d7c8257d9

1 changed files with 23 additions and 34 deletions

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net/sched/sch_prio.c

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