linux-kernel - Re: (trivia) remove useless typecast around `jif' variable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.61.0703051724520.24366@yvahk01.tjqt.qr>
Date:	Mon, 5 Mar 2007 17:29:35 +0100 (MET)
From:	Jan Engelhardt <jengelh@...ux01.gwdg.de>
To:	Michael Tokarev <mjt@....msk.ru>
cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: (trivia) remove useless typecast around `jif' variable

On Mar 5 2007 19:12, Michael Tokarev wrote:

>Date: Mon,  5 Mar 2007 19:12:51 +0300 (MSK)
>From: Michael Tokarev <mjt@....msk.ru>
>To: undisclosed-recipients:  ;

I have no clue what you sent it to, so I added linux-kernel again.



>Subject: (trivia) remove useless typecast around `jif' variable
>
>in fs/proc/proc_misc.c:show_stat() routine (which handles /proc/stat
>file), there's a local variable named 'jif' of type unsigned long,
>declared as following:
>
>static int show_stat(struct seq_file *p, void *v)
>{
>        unsigned long jif;
>
>But later on, it's explicitly casted to (unsigned long) in printf().
>Remove the useless cast, to let the compiler to do the work for us
>in case we'll want to use different type here (say, u64 or something).

In case we wanted to use different types, we would also have to
change the accompanying %lu into %llu. Only changing jif to u64 will
cause a problem, as the compiler does _not_ automatically
promote/demote types in varargs that already have a certain size. In
other words,

int foo(unsigned long x)
{
        printk("%llu\n", x);  /* and */
        printk("%lu\n", x);
}

will throw a warning (rightfully if you ask me).



Jan
-- 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/