From: Arnd Bergmann <arnd@arndb.de>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>, Andrew Morton <akpm@osdl.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -mm 1/3] swsusp: Add ioctl for swap files support
Date: Sat, 30 Sep 2006 22:37:21 +0200 [thread overview]
Message-ID: <200609302237.22086.arnd@arndb.de> (raw)
In-Reply-To: <200609302158.03692.rjw@sisk.pl>
Am Saturday 30 September 2006 21:58 schrieb Rafael J. Wysocki:
> > Your definition looks wrong, '_IOW(SNAPSHOT_IOC_MAGIC, 13, void *)' means
> > your ioctl passes a pointer to a 'void *'.
> >
> > You probably mean
> >
> > #define SNAPSHOT_SET_SWAP_AREA _IOW(SNAPSHOT_IOC_MAGIC, 13, \
> > struct resume_swap_area)
>
> No. I mean the ioctl passes a pointer, the size of which is sizeof(void *).
That's a very bad thing to do. It means that the ioctl number is different
between 32 and 64 bit and you need to write a conversion handler that
first reads your pointer and then then writes the real data.
Also, it needs to be at least _IOR() in the case you're describing,
because the pointer is read, not written (I hope).
Arnd <><
next prev parent reply other threads:[~2006-09-30 20:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-28 22:05 [PATCH -mm 0/3] swsusp: Add ioctl for swap files support and update documentation Rafael J. Wysocki
2006-09-28 22:13 ` [PATCH -mm 1/3] swsusp: Add ioctl for swap files support Rafael J. Wysocki
2006-09-28 22:42 ` Andrew Morton
2006-09-28 22:58 ` Rafael J. Wysocki
2006-09-28 23:03 ` Pavel Machek
2006-09-28 23:35 ` Rafael J. Wysocki
2006-09-28 23:39 ` Pavel Machek
2006-09-30 14:15 ` Arnd Bergmann
2006-09-30 19:58 ` Rafael J. Wysocki
2006-09-30 20:37 ` Arnd Bergmann [this message]
2006-09-30 22:04 ` Rafael J. Wysocki
2006-10-01 21:52 ` Arnd Bergmann
2006-09-28 23:04 ` Pavel Machek
2006-09-28 22:17 ` [PATCH -mm 2/3] swsusp: Update userland interface documentation Rafael J. Wysocki
2006-09-28 22:19 ` [PATCH -mm 3/3] swsusp: Document testing code Rafael J. Wysocki
2006-09-28 22:37 ` Pavel Machek
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