linux-kernel - Re: [PATCH] lib/vsprintf.c:Avoid extra operation in dentry

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Message-ID: <CA+HOOshzYPvsfhw82vM2mS=JwRsyQQtbS56FxCPF7epOibiRoQ@mail.gmail.com>
Date:	Tue, 17 Feb 2015 22:41:49 +0530
From:	Anshul Garg <aksgarg1989@...il.com>
To:	Richard Weinberger <richard.weinberger@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	"anshul.g@...sung.com" <anshul.g@...sung.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] lib/vsprintf.c:Avoid extra operation in dentry_name

Yes suggested code modification will break if (p==d) branch is not taken.
Thanks for pointing out this point.

So its better to keep code as it is.

On Tue, Feb 17, 2015 at 12:44 AM, Richard Weinberger
<richard.weinberger@...il.com> wrote:
> On Mon, Feb 16, 2015 at 7:49 PM, Anshul Garg <aksgarg1989@...il.com> wrote:
>> From: Anshul Garg <aksgarg1989@...il.com>
>>
>> Remove unnecessary increment and decrement operation
>> in dentry_name function as after increment operation
>> loop is breaked and then decrement operation is
>> performed. So remove increment and decrement operation
>> from the function.
>>
>> Signed-off-by: Anshul Garg <aksgarg1989@...il.com>
>> ---
>>  lib/vsprintf.c |    3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
>> index ec337f6..2a38105 100644
>> --- a/lib/vsprintf.c
>> +++ b/lib/vsprintf.c
>> @@ -576,11 +576,10 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
>>                 if (p == d) {
>>                         if (i)
>>                                 array[i] = "";
>> -                       i++;
>>                         break;
>>                 }
>>         }
>> -       s = array[--i];
>> +       s = array[i];
>>         for (n = 0; n != spec.precision; n++, buf++) {
>>                 char c = *s++;
>>                 if (!c) {
>
> What if the if (d == d) branch is not taken?
> Does the code then really behave exactly as before?
>
> --
> Thanks,
> //richard
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