Re: [PATCH v2 net] net_sched: prio: insure proper transactional behavior
From: Cong Wang <hidden>
Date: 2016-06-13 21:21:37
On Mon, Jun 13, 2016 at 11:33 AM, Eric Dumazet [off-list ref] wrote:
From: Eric Dumazet <edumazet@google.com>
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: cbdf45116478 ("net_sched: prio: properly report out of memory errors")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Cong Wang <redacted>Looks good to me, Acked-by: Cong Wang <redacted> Thanks!