From: Cong Wang <amwang@redhat.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: opurdila@ixiacom.com, eric.dumazet@gmail.com,
netdev@vger.kernel.org, nhorman@tuxdriver.com,
davem@davemloft.net, ebiederm@xmission.com,
linux-kernel@vger.kernel.org
Subject: Re: [Patch 3/3] net: reserve ports for applications using fixed port numbers
Date: Tue, 13 Apr 2010 16:48:32 +0800 [thread overview]
Message-ID: <4BC42FE0.4040601@redhat.com> (raw)
In-Reply-To: <4BC41994.7030707@redhat.com>
Cong Wang wrote:
> Tetsuo Handa wrote:
>> Hello.
>>
>>> --- linux-2.6.orig/drivers/infiniband/core/cma.c
>>> +++ linux-2.6/drivers/infiniband/core/cma.c
>>> @@ -1980,6 +1980,8 @@ retry:
>>> /* FIXME: add proper port randomization per like inet_csk_get_port */
>>> do {
>>> ret = idr_get_new_above(ps, bind_list, next_port, &port);
>>> + if (!ret && inet_is_reserved_local_port(port))
>>> + ret = -EAGAIN;
>>> } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));
>>>
>>> if (ret)
>>>
>> I think above part is wrong. Below program
> ...
>> This result suggests that above loop will continue until idr_pre_get() fails
>> due to out of memory if all ports were reserved.
>>
>> Also, if idr_get_new_above() returned 0, bind_list (which is a kmalloc()ed
>> pointer) is already installed into a free slot (see comment on
>> idr_get_new_above_int()). Thus, simply calling idr_get_new_above() again will
>> install the same pointer into multiple slots. I guess it will malfunction later.
>
> Thanks for testing!
>
> How about:
>
> + if (!ret && inet_is_reserved_local_port(port))
> + ret = -EBUSY;
>
> ? So that it will break the loop and return error.
>
Or use the similar trick:
int tries = 10;
...
if(!ret && inet_is_reserved_local_port(port)) {
if (tries--)
ret = -EAGAIN;
else
ret = -EBUSY;
}
Any comments?
next prev parent reply other threads:[~2010-04-13 8:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-12 10:03 [Patch v8 0/3] net: reserve ports for applications using fixed port numbers Amerigo Wang
2010-04-12 10:04 ` [Patch 1/3] sysctl: refactor integer handling proc code Amerigo Wang
2010-04-13 11:18 ` Alexey Dobriyan
2010-04-13 7:35 ` Cong Wang
2010-04-12 10:04 ` [Patch 2/3] sysctl: add proc_do_large_bitmap Amerigo Wang
2010-04-12 10:04 ` [Patch 3/3] net: reserve ports for applications using fixed port numbers Amerigo Wang
2010-04-13 1:21 ` Tetsuo Handa
2010-04-13 7:13 ` Cong Wang
2010-04-13 8:48 ` Cong Wang [this message]
2010-04-13 13:07 ` Tetsuo Handa
2010-04-13 16:32 ` Sean Hefty
2010-04-14 2:01 ` [PATCH] Infiniband: Randomize local port allocation penguin-kernel
2010-04-14 4:38 ` Cong Wang
2010-04-15 0:01 ` Sean Hefty
2010-04-15 2:29 ` Tetsuo Handa
2010-04-15 19:55 ` [PATCH] rdma/cm: " Sean Hefty
2010-04-16 2:22 ` Cong Wang
2010-04-16 13:54 ` Tetsuo Handa
2010-04-16 20:30 ` David Miller
2010-04-20 4:34 ` Cong Wang
2010-04-21 23:19 ` [PATCH] Infiniband: " Roland Dreier
2010-04-21 23:22 ` Roland Dreier
-- strict thread matches above, loose matches on Subject: below --
2010-05-05 10:26 [Patch v10 0/3] net: reserve ports for applications using fixed port numbers Amerigo Wang
2010-05-05 10:27 ` [Patch 3/3] " Amerigo Wang
2010-04-30 8:25 [Patch v9 0/3] " Amerigo Wang
2010-04-30 8:25 ` [Patch 3/3] " Amerigo Wang
2010-04-09 10:10 [Patch v7 0/3] " Amerigo Wang
2010-04-09 10:11 ` [Patch 3/3] " Amerigo Wang
2010-04-09 13:21 ` Tetsuo Handa
2010-04-12 6:52 ` Cong Wang
2010-04-12 7:06 ` Tetsuo Handa
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