From: Chen Gang <gang.chen@asianux•com>
To: "Chas Williams (CONTRACTOR)" <chas@cmf•nrl.navy.mil>
Cc: David Miller <davem@davemloft•net>, netdev <netdev@vger•kernel.org>
Subject: Re: [Suggestion] net/atm : for sprintf, need check the total write length whether larger than a page.
Date: Wed, 05 Dec 2012 13:59:26 +0800 [thread overview]
Message-ID: <50BEE2BE.2030704@asianux.com> (raw)
In-Reply-To: <50BEDE4E.8010408@asianux.com>
于 2012年12月05日 13:40, Chen Gang 写道:
> 于 2012年12月05日 12:56, Chen Gang 写道:
>>>>>>>> - pos += sprintf(pos, "\n");
>>>>>>>> + count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
>>>> ..
>>>>>> need we judge whether count >= PAGE_SIZE ?
>>>>
>>>> count will eventually make PAGE_SIZE - count reach 0 at which point,
>>>> scnprintf() won't be able to write into the buffer.
>> I also think so.
>>
>> I think, maybe it will be better to break the loop when we already
>> know that "count >= PAGE_SIZE" (it can save waste looping, although it
>> seems unlikly happen, for example, using unlikly(...) ).
>>
>> By the way:
>> will it be better that always let "\n" at the end ?
>> (if count == PAGE_SIZE in a loop, we can not let "\n" at the end).
>
> oh, sorry ! count will never >= PAGE_SIZE.
>
> I think let "PAGE_SIZE - 2" instead of "PAGE_SIZE" in the loop, so we
> can make the room for the end of "\n".
>
>
>
sorry, "PAGE_SIZE - 1" is enough, not need "PAGE_SIZE - 2".
--
Chen Gang
Asianux Corporation
next prev parent reply other threads:[~2012-12-05 5:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-21 4:29 [Suggestion] net/atm : for sprintf, need check the total write length whether larger than a page Chen Gang
2012-12-03 8:56 ` Chen Gang
2012-12-03 15:48 ` chas williams - CONTRACTOR
2012-12-05 1:28 ` Chen Gang
2012-12-04 3:46 ` Chas Williams (CONTRACTOR)
2012-12-05 1:26 ` Chen Gang
2012-12-05 3:57 ` Chas Williams (CONTRACTOR)
2012-12-05 4:56 ` Chen Gang
2012-12-05 5:40 ` Chen Gang
2012-12-05 5:59 ` Chen Gang [this message]
2012-12-05 14:55 ` chas williams - CONTRACTOR
2012-12-06 1:15 ` Chen Gang
2012-12-06 9:05 ` Chen Gang
2012-12-06 14:08 ` chas williams - CONTRACTOR
2012-12-07 1:07 ` Chen Gang
2012-12-10 1:39 ` Chen Gang
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