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 12:56:45 +0800 [thread overview]
Message-ID: <50BED40D.9080100@asianux.com> (raw)
In-Reply-To: <201212050357.qB53vHvT022706@thirdoffive.cmf.nrl.navy.mil>
于 2012年12月05日 11:57, Chas Williams (CONTRACTOR) 写道:
> In message <50BEA2CB.9000800@asianux•com>,Chen Gang writes:
>>> - for (i = 0; i < (ESI_LEN - 1); i++)
>>> - pos += sprintf(pos, "%02x:", adev->esi[i]);
>>> - pos += sprintf(pos, "%02x\n", adev->esi[i]);
>>>
>>> - return pos - buf;
>>> + return scnprintf(buf, PAGE_SIZE, "%pM\n", adev->esi);
>>> }
>>>
>>
>> "%p" seems print a pointer, not contents of pointer (is it correct ?)
>> will it change the original display format to outside ?
>
> %pM means format this pointer as a mac address. it didnt exist when the
> atm stack was originally written but can be used now to save a bit of
> messy code.
>
it is my fault. thank you
:-)
>>> - 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).
I think what I said above are minor, if you think, for this patch, do
not need consider them, it is ok (at least for me, it is true).
:-)
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>
--
Chen Gang
Asianux Corporation
next prev parent reply other threads:[~2012-12-05 4:55 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 [this message]
2012-12-05 5:40 ` Chen Gang
2012-12-05 5:59 ` Chen Gang
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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