From: Arnd Bergmann <arnd@arndb.de>
To: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com>
Cc: andrew.chih.howe.khor@intel.com, joel.clark@intel.com, "Wang,
Yong Y" <yong.y.wang@intel.com>,
qi.wang@intel.com, "LKML" <linux-kernel@vger.kernel.org>,
linux-i2c@vger.kernel.org,
"Ben Dooks \(embedded platforms\)" <ben-linux@fluff.org>,
"Jean Delvare \(PC drivers, core\)" <khali@linux-fr.org>
Subject: Re: [PATCH] I2C driver of Topcliff PCH
Date: Tue, 20 Jul 2010 11:29:52 +0200 [thread overview]
Message-ID: <201007201129.53110.arnd@arndb.de> (raw)
In-Reply-To: <000601cb27e4$3768c170$66f8800a@maildom.okisemi.com>
On Tuesday 20 July 2010, Masayuki Ohtake wrote:
> > > @@ -147,6 +148,11 @@ static ssize_t i2cdev_read(struct file *file, char __user *buf, size_t count,
> > > if (tmp == NULL)
> > > return -ENOMEM;
> > >
> > > + if (copy_from_user(tmp, buf, count)) {
> > > + kfree(tmp);
> > > + return -EFAULT;
> > > + }
> > > +
> > > pr_debug("i2c-dev: i2c-%d reading %zu bytes.\n",
> > > iminor(file->f_path.dentry->d_inode), count);
> >
> >
> > A read function should not do copy_from_user, only copy_to_user.
> > If you are worried about returning invalid data from kernel space,
> > better use kzalloc instead of kmalloc to get the buffer.
>
> Our I2C HW has special mode.
> To control the mode, our i2c driver has copy_from_user.
That is a highly unusual interface and I would definitely not recommend doing
this. Please use an ioctl operation for anything that has both input and output
data.
Arnd
next prev parent reply other threads:[~2010-07-20 9:30 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-22 5:33 [PATCH] Topcliff PHUB: Generate PacketHub driver Masayuki Ohtak
2010-06-22 10:33 ` Masayuki Ohtak
2010-06-22 22:12 ` Andrew Morton
2010-06-23 0:31 ` Masayuki Ohtake
2010-06-22 11:30 ` Arnd Bergmann
2010-06-22 13:52 ` Yong Wang
2010-06-29 23:31 ` Andy Isaacson
2010-06-30 5:58 ` Masayuki Ohtake
2010-06-30 18:28 ` Andy Isaacson
2010-07-01 4:08 ` Masayuki Ohtake
2010-06-30 7:51 ` [PATCH] Packet hub driver of Topcliff PCH Masayuki Ohtak
2010-06-30 18:05 ` Randy Dunlap
2010-07-01 2:52 ` Masayuki Ohtake
2010-07-01 5:14 ` Masayuki Ohtak
2010-07-01 6:58 ` Andy Isaacson
2010-07-01 10:13 ` Masayuki Ohtake
2010-07-01 10:38 ` Masayuki Ohtak
2010-07-01 15:44 ` Randy Dunlap
2010-07-05 7:20 ` Masayuki Ohtak
2010-07-05 15:04 ` Arnd Bergmann
2010-07-06 15:58 ` Randy Dunlap
2010-07-06 6:20 ` Masayuki Ohtak
2010-07-06 6:30 ` Arnd Bergmann
2010-07-07 1:19 ` Yong Wang
2010-07-09 20:00 ` Andrew Morton
2010-07-12 1:25 ` Masayuki Ohtake
2010-07-15 7:25 ` Masayuki Ohtak
2010-07-15 7:42 ` [PATCH] I2C " Masayuki Ohtak
2010-07-15 19:35 ` Arnd Bergmann
2010-07-20 0:05 ` Masayuki Ohtake
2010-07-20 4:55 ` Masayuki Ohtake
2010-07-20 9:27 ` Arnd Bergmann
2010-07-20 12:38 ` Masayuki Ohtake
2010-07-20 8:19 ` Masayuki Ohtake
2010-07-20 9:29 ` Arnd Bergmann [this message]
2010-07-20 12:40 ` Masayuki Ohtake
2010-07-21 6:46 ` Masayuki Ohtak
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201007201129.53110.arnd@arndb.de \
--to=arnd@arndb.de \
--cc=andrew.chih.howe.khor@intel.com \
--cc=ben-linux@fluff.org \
--cc=joel.clark@intel.com \
--cc=khali@linux-fr.org \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masa-korg@dsn.okisemi.com \
--cc=qi.wang@intel.com \
--cc=yong.y.wang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox