From: Arnd Bergmann <arnd@arndb.de>
To: "Michał Mirosław" <mirqus@gmail.com>
Cc: John Calixto <john.calixto@modsystems.com>,
linux-mmc@vger.kernel.org,
Andrei Warkentin <andreiw@motorola.com>,
Chris Ball <cjb@laptop.org>
Subject: Re: [PATCH v6] mmc: Add mmc CMD+ACMD passthrough ioctl
Date: Thu, 21 Apr 2011 14:39:14 +0200 [thread overview]
Message-ID: <201104211439.14510.arnd@arndb.de> (raw)
In-Reply-To: <BANLkTikTBK+0_KLjcB_sk4kF+a_vdaOckQ@mail.gmail.com>
On Thursday 21 April 2011, Michał Mirosław wrote:
> W dniu 21 kwietnia 2011 13:15 użytkownik Arnd Bergmann <arnd@arndb.de> napisał:
> static int mmc_blk_compat_ioctl(struct block_device *bdev, fmode_t mode,
> unsigned int cmd, unsigned long arg)
> {
> struct mmc_ioc_cmd blk;
>
> if (cmd != MMC_IOC_CMD)
> return -EINVAL;
>
> copy_from_user(compat_ptr(arg), &blk) ...
> blk.data_ptr = compat_ptr(blk.__data_ptr_storage32);
>
> return mmc_blk_ioctl_cmd(bdev, &blk);
> }
Yes, this works, but it requires having a compat_ioctl() handler function that
knows about the data structure, which we generally try to avoid.
The same method would even work if you only had a pointer member in the
structure and did not even attempt to make the structure compatible.
Arnd
next prev parent reply other threads:[~2011-04-21 12:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-14 0:34 v6 changelog for mmc ioctl patch John Calixto
2011-04-14 0:38 ` [PATCH v6] mmc: Add mmc CMD+ACMD passthrough ioctl John Calixto
2011-04-20 17:12 ` John Calixto
2011-04-20 17:29 ` Chris Ball
2011-04-21 10:47 ` Arnd Bergmann
2011-04-20 17:31 ` Michał Mirosław
2011-04-20 17:38 ` John Calixto
2011-04-20 18:06 ` Michał Mirosław
2011-04-20 18:23 ` Michał Mirosław
2011-04-20 19:06 ` John Calixto
2011-04-20 19:17 ` Arnd Bergmann
2011-04-20 19:34 ` John Calixto
2011-04-20 19:38 ` Arnd Bergmann
2011-04-20 19:46 ` Michał Mirosław
2011-04-20 20:47 ` John Calixto
2011-04-20 22:28 ` Chris Ball
2011-04-21 5:11 ` Arnd Bergmann
2011-04-21 10:28 ` Michał Mirosław
2011-04-21 11:15 ` Arnd Bergmann
2011-04-21 11:47 ` Michał Mirosław
2011-04-21 12:39 ` Arnd Bergmann [this message]
2011-04-21 13:40 ` Michał Mirosław
2011-04-20 22:13 ` Chris Ball
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