linux-kernel - Re: [PATCH] filldir write data missing size

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Message-ID: <87r69pk51q.fsf@devron.myhome.or.jp>
Date:	Sun, 20 Jul 2008 05:11:29 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Yoshinori Sato <ysato@...rs.sourceforge.jp>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] filldir write data missing size

Yoshinori Sato <ysato@...rs.sourceforge.jp> writes:

>> > -		if (__put_user(offset, &dirent->d_off))
>> > +		if (__put_user((unsigned long)offset, &dirent->d_off))
>> 
>> Um.. __put_user() should be already doing it automatically..
>
> I'm mistake.
>
> I checked object, and found bad code.
> This problem fix __put_user.

Um.. Could you explain the detail of problem? Is this a workaround or
something for the bug of some compiler?  If so, shouldn't we fix
__put_user() instead of caller?

E.g. the following or something fixes it? (btw, this is for x86)

#define __put_user(x, ptr) ({						\
 	/* Since some compiler generates wrong code, we need __v.?? */	\
        __typeof__(*(ptr)) __v = (x);					\
	__put_user_nocheck(__v, (ptr), sizeof(*(ptr)));			\
})
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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