Commit Graph

68 Commits

Author SHA1 Message Date
Al Viro 7d5cb45655 i2c compat ioctls: move to ->compat_ioctl()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-09-20 01:02:27 -04:00
Vlad Tsyrklevich 30f939feae i2c: fix kernel memory disclosure in dev interface
i2c_smbus_xfer() does not always fill an entire block, allowing
kernel stack memory disclosure through the temp variable. Clear
it before it's read to.

Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
2017-01-12 20:06:10 +01:00
viresh kumar 5136ed4fcb i2c-dev: don't get i2c adapter via i2c_dev
There is no code protecting i2c_dev to be freed after it is returned
from i2c_dev_get_by_minor() and using it to access the value which we
already have (minor) isn't safe really.

Avoid using it and get the adapter directly from 'minor'.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-07-08 10:29:31 +09:00
Dan Carpenter e6be18f6d6 i2c: dev: use after free in detach
The call to put_i2c_dev() frees "i2c_dev" so there is a use after
free when we call cdev_del(&i2c_dev->cdev).

Fixes: d6760b14d4 ('i2c: dev: switch from register_chrdev to cdev API')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-05-28 17:37:42 +02:00
Wolfram Sang 72a71f869c i2c: dev: don't start function name with 'return'
I stumbled multiple times over 'return_i2c_dev', especially before the
actual 'return res'. It makes the code hard to read, so reanme the
function to 'put_i2c_dev' which also better matches 'get_free_i2c_dev'.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-05-27 13:13:01 +02:00
Erico Nunes d6760b14d4 i2c: dev: switch from register_chrdev to cdev API
i2c-dev had never moved away from the older register_chrdev interface to
implement its char device registration. The register_chrdev API has the
limitation of enabling only up to 256 i2c-dev busses to exist.

Large platforms with lots of i2c devices (i.e. pluggable transceivers)
with dedicated busses may have to exceed that limit.
In particular, there are also platforms making use of the i2c bus
multiplexing API, which instantiates a virtual bus for each possible
multiplexed selection.

This patch removes the register_chrdev usage and replaces it with the
less old cdev API, which takes away the 256 i2c-dev bus limitation.
It should not have any other impact for i2c bus drivers or user space.

This patch has been tested on qemu x86 and qemu powerpc platforms with
the aid of a module which adds and removes 5000 virtual i2c busses, as
well as validated on an existing powerpc hardware platform which makes
use of the i2c bus multiplexing API.
i2c-dev busses with device minor numbers larger than 256 have also been
validated to work with the existing i2c-tools.

Signed-off-by: Erico Nunes <erico.nunes@datacom.ind.br>
[wsa: kept includes sorted]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-05-26 21:18:57 +02:00
Wolfram Sang a87660737f i2c: i2c-dev: sort includes
I request this for drivers, so the core should adhere to sorted includes as
well.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-02-20 23:33:38 +01:00
Jean Delvare 9e685c84c2 i2c-dev: Fix I2C_SLAVE ioctl comment
The first part of the comment is wrong since November 2007, delete it.

The second part of the comment is related to I2C_PEC, not I2C_SLAVE, so
move it where it belongs.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23 23:26:44 +02:00
Jean Delvare c57d3e7a93 i2c-dev: Fix typo in ioctl name reference
The ioctl is named I2C_RDWR for "I2C read/write". But references to it
were misspelled "rdrw". Fix them.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23 23:26:43 +02:00
Wolfram Sang ca1f8da9ac i2c: remove FSF address
We have a central copy of the GPL for that. Some addresses were already
outdated.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
2014-11-07 18:35:33 +01:00
Guenter Roeck 45f176aea6 i2c: i2c-dev: Create 'name' attribute automatically
The 'name' attribute is needed for all i2c-dev class devices, meaning
it can be created automatically by pointing to it in the class data
structure. This simplifies the code and reduces the probability for race
conditions (the name attribute should exist by the time the device is
announced to user space).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-09-30 06:02:31 +02:00
Al Viro 496ad9aa8e new helper: file_inode(file)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-22 23:31:31 -05:00
Jean Delvare 838bfa6049 i2c-dev: Add support for I2C_M_RECV_LEN
As the bus driver side implementation of I2C_M_RECV_LEN is heavily
tied to SMBus, we can't support received length over 32 bytes, but
let's at least support that.

In practice, the caller will have to setup a buffer large enough to
cover the case where received length byte has value 32, so minimum
32 + 1 = 33 bytes, possibly more if there is a fixed number of bytes
added for the specific slave (for example a checksum.)

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
2012-05-30 10:55:34 +02:00
Jean Delvare 5694f8a888 i2c: Update the FSF address
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2012-03-26 21:47:19 +02:00
Thomas Meyer a699ed6f1f i2c-dev: Use memdup_user
Use memdup_user rather than duplicating its implementation.
This is a little bit restricted to reduce false positives.

The semantic patch that makes this output is available
in scripts/coccinelle/api/memdup_user.cocci.

More information about semantic patching is available at
http://coccinelle.lip6.fr/

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2012-01-12 20:32:04 +01:00
Shubhrajyoti D eff245c82f i2c: Make i2cdev_notifier_call static
The function i2cdev_notifier_call is used only in i2c-dev file
making it static.
Also removes the following sparse warning

drivers/i2c/i2c-dev.c:582:5: warning: symbol 'i2cdev_notifier_call'
was not declared. Should it be static?

Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2011-11-23 11:33:07 +01:00
Jean Delvare 9ea3e941d1 i2c-dev: Use standard bus notification mechanism
Use the standard driver core mechanism to keep track of i2c adapters
present on the system: i2c_for_each_dev and a notifier. This will let
us deprecate and ultimately remove the legacy attach_adapter and
detach_adapter callbacks in i2c_driver.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2011-03-20 14:50:52 +01:00
Jean Delvare 97cc4d49cf i2c: Let i2c_parent_is_i2c_adapter return the parent adapter
This makes the calling site's code clearer IMHO.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Michael Lawnick <ml.lawnick@gmx.de>
2010-10-24 18:16:57 +02:00
Michael Lawnick 0826374bff i2c: Multiplexed I2C bus core support
Add multiplexed bus core support. I2C multiplexer and switches
like pca954x get instantiated as new adapters per port.

Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-08-11 18:21:02 +02:00
Julia Lawall f1c2e33c29 i2c-dev: Use memdup_user
Use memdup_user when user data is immediately copied into the allocated
region.  Note that in the second case, the ++i is no longer necessary, as
the last value is already freed if needed by the call to memdup_user.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@

-  to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+  to = memdup_user(from,size);
   if (
-      to==NULL
+      IS_ERR(to)
                 || ...) {
   <+... when != goto l1;
-  -ENOMEM
+  PTR_ERR(to)
   ...+>
   }
-  if (copy_from_user(to, from, size) != 0) {
-    <+... when != goto l2;
-    -EFAULT
-    ...+>
-  }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-08-11 18:20:55 +02:00
Joe Perches 35a56c5b82 i2c-dev: Remove unnecessary kmalloc casts
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-08-11 18:20:54 +02:00
Farid Hammane ae5624fc36 i2c-dev: Fix all coding style issues
Fix all coding style issues found by checkpatch.pl.

Signed-off-by: Farid Hammane <farid.hammane@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-05-21 18:40:59 +02:00
H Hartley Sweeten 0be16c3061 i2c-dev: Remove unnecessary casts
The private_data member of struct file is a void *, there is no need
to cast it.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-05-21 18:40:57 +02:00
Vincent Sanders 9669f54194 i2c: Remove big kernel lock from i2cdev_open
The BKL is held over a kmalloc so cannot protect anything beyond that.
The two calls before the kmalloc have their own locking.
Improve device open function by removing the now unnecessary ret variable

Signed-off-by: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-12-06 17:06:26 +01:00
Jean Delvare cd97f39b7c i2c-dev: Clarify the unit of ioctl I2C_TIMEOUT
The unit in which user-space can set the bus timeout value is jiffies
for historical reasons (back when HZ was always 100.) This is however
not good because user-space doesn't know how long a jiffy lasts. The
timeout value should instead be set in a fixed time unit. Given the
original value of HZ, this unit should be 10 ms, for compatibility.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2009-02-24 19:19:49 +01:00
Greg Kroah-Hartman a9b12619f7 device create: misc: convert device_create_drvdata to device_create
Now that device_create() has been audited, rename things back to the
original call to be sane.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-16 09:24:43 -07:00
Sven Wegener e74783ec3c i2c-dev: Return correct error code on class_create() failure
We need to convert the error pointer from class_create(), else we'll return the
successful return code from register_chrdev() on failure.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-09-24 13:39:21 +02:00
David Brownell 2ce5b34fd5 i2c: correct some size_t printk formats
Fix various printk format strings where %zd was passed a size_t;
those should be %zu instead.  (Courtesy of a version of GCC which
warns when these details are wrong.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-08-10 22:56:16 +02:00
Greg Kroah-Hartman 1cc4376c25 device create: i2c: convert device_create to device_create_drvdata
device_create() is race-prone, so use the race-free
device_create_drvdata() instead as device_create() is going away.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21 21:54:42 -07:00
Linus Torvalds dc221eae08 Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
* 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6: (56 commits)
  i2c: Add detection capability to new-style drivers
  i2c: Call client_unregister for new-style devices too
  i2c: Clean up old chip drivers
  i2c-ibm_iic: Register child nodes
  i2c: New-style EEPROM driver using device IDs
  i2c: Export the i2c_bus_type symbol
  i2c-au1550: Fix PM support
  i2c-dev: Delete empty detach_client callback
  i2c: Drop stray references to lm_sensors
  i2c: Check for ACPI resource conflicts
  i2c-ocores: basic PM support
  i2c-sibyte: SWARM I2C board initialization
  i2c-i801: Fix handling of error conditions
  i2c-i801: Rename local variable temp to status
  i2c-i801: Properly report bus arbitration loss
  i2c-i801: Remove verbose debugging messages
  i2c-algo-pcf: Drop unused struct members
  i2c-algo-pcf: Multi-master lost-arbitration improvement
  i2c: Deprecate the legacy gpio drivers
  i2c-pxa: Initialize early
  ...
2008-07-15 11:16:05 -07:00
Jean Delvare f6a7110520 i2c-dev: Delete empty detach_client callback
Implementing detach_client is optional, so there is no point in
an empty implementation.

Likewise, i2c driver IDs are optional, and we don't need one.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-07-14 22:38:34 +02:00
Alan Cox 77e38bffe0 i2c: Push ioctl BKL down into the i2c code
This is part of the effort to get rid of the BKL.

[JD: In fact i2c-dev doesn't need more locking than is already done
for the other i2c drivers, so we can simply switch to unlocked_ioctl.]

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-07-14 22:38:27 +02:00
Jonathan Corbet 3db633ee35 i2c: cdev lock_kernel() pushdown
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-05-18 15:43:40 -06:00
Jean Delvare dba7997a87 i2c-dev: Split i2cdev_ioctl
Split the handling of the I2C_RDWR and I2C_SMBUS ioctls to their own
functions. This limits the stack usage, saves one level of indentation
and makes the code more readable.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-04-22 22:16:47 +02:00
David Brownell 9b766b814d i2c: Stop using the redundant client list
The i2c_adapter.clients list of i2c_client nodes duplicates driver
model state.  This patch starts removing that list, letting us remove
most existing users of those i2c-core lists.

 * The core I2C code now iterates over the driver model's list instead
   of the i2c-internal one in some places where it's safe:
      - Passing a command/ioctl to each client, a mechanims
        used almost exclusively by DVB adapters;
      - Device address checking, in both i2c-core and i2c-dev.

 * Provide i2c_verify_client() to use with driver model iterators.

 * Flag the relevant i2c_adapter and i2c_client fields as deprecated,
   to help prevent new users from appearing.

For the moment the list needs to stick around, since some issues show
up when deleting devices created by legacy I2C drivers.  (They don't
follow standard driver model rules.  Removing those devices can cause
self-deadlocks.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-01-27 18:14:51 +01:00
Joe Perches 96acafe05f i2c: Spelling fixes
[JD: One more fix in i2c-dev.]

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-01-14 21:53:30 +01:00
Jean Delvare bd4217d8c6 i2c-dev: Unbound new-style i2c clients aren't busy
Let i2c-dev deal properly with new-style i2c clients. Instead of
considering them always busy, it needs to check wether a driver is
bound to them or not.

This is still not completely correct, as the client could become
busy later, but the same problem already existed before new-style
clients were introduced. We'll want to fix it someday.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
2007-11-15 19:24:01 +01:00
David Brownell 907135aaa0 i2c-dev: "how does it work" comments
This adds some "how does this work" comments to the i2c-dev driver,
plus separators between the three main components:

  - The parallel list of i2c_adapters ("i2c_dev_list"), each of which
    gets a "struct i2c_dev" and a /dev/i2c-X character special file.

  - An i2cdev_driver gets adapter add/remove notifications, which are
    used to maintain that list of adapters.

  - Special file operations, which let userspace talk either directly to
    the adapter (for i2c_msg operations) or through cached addressing info
    using an anonymous i2c_client (never registered anywhere).

Plus there's the usual module load/unload record keeping.

After making sense of this code, I think that the anonymous i2c_client
is pretty shady.  But since it's never registered, using this code with
a system set up for "new style" I2C drivers is no more complicated than
always using the I2C_SLAVE_FORCE ioctl (instead of I2C_SLAVE).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-11-15 19:24:01 +01:00
David Brownell 53be795934 i2c: Remove i2c_algorithm.algo_control()
This removes:

 - An effectively unused hook:  i2c_algorithm.algo_control.

 - The i2c_control() call, used only by i2c-dev to call that
   unused hook or set two barely supported adapter params.

   (That param setting moves into i2c-dev.c ... still iffy
   due to lack of locking, but no other changes.)

As shown by diffstat, this is a net code shrink.  It also reduces the
complexity of the I2C adapter and /dev interfaces.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-10-13 23:56:32 +02:00
David Brownell e265cfa19c i2c-dev: Reject I2C_M_RECV_LEN
The I2C_M_RECV_LEN calling convention for i2c_mesg.flags involves
playing games with reported buffer lengths.  (They start out less
than their actual size, and the length is then modified to reflect
how many bytes were delivered ... which one hopes is less than the
presumed actual size.)  Refuse to play such error prone games across
the boundary between userspace and kernel.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-10-13 23:56:31 +02:00
Jean Delvare 4b2643d7d9 i2c: Fix the i2c_smbus_read_i2c_block_data() prototype
Let the drivers specify how many bytes they want to read with
i2c_smbus_read_i2c_block_data(). So far, the block count was
hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense.
Many driver authors complained about this before, and I believe it's
about time to fix it. Right now, authors have to do technically stupid
things, such as individual byte reads or full-fledged I2C messaging,
to work around the problem. We do not want to encourage that.

I even found that some bus drivers (e.g. i2c-amd8111) already
implemented I2C block read the "right" way, that is, they didn't
follow the old, broken standard. The fact that it was never noticed
before just shows how little i2c_smbus_read_i2c_block_data() was used,
which isn't that surprising given how broken its prototype was so far.

There are some obvious compatiblity considerations:
* This changes the i2c_smbus_read_i2c_block_data() prototype. Users
  outside the kernel tree will notice at compilation time, and will
  have to update their code.
* User-space has access to i2c_smbus_xfer() directly using i2c-dev, so
  the changed expectations would affect tools such as i2cdump. In order
  to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA
  a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the
  old numeric value. When i2c-dev receives a transaction with the
  old value, it can convert it to the new format on the fly.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-07-12 14:12:29 +02:00
Randy Dunlap e63340ae6b header cleaning: don't include smp_lock.h when not used
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:07 -07:00
Arjan van de Ven 2b8693c061 [PATCH] mark struct file_operations const 3
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00
Jean Delvare 07125ab2c2 i2c: Refactor a kfree in i2c-dev
Refactor kfree(i2c_dev) into return_i2c_dev(). This saves some
code and makes more sense, as the memory is allocated in
get_free_i2c_dev().

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-10 21:21:33 +01:00
Akinobu Mita 3bacb36db0 i2c: Fix return value check in i2c-dev
device_create() returns error code as pointer on failures.
This patch checks the return value of device_create() by using IS_ERR().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:33 +01:00
David Brownell 438d6c2c01 i2c: Whitespace cleanups
Remove extraneous whitespace from various i2c headers and core files,
like space-before-tab and whitespace at end of line.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:31 +01:00
Jean Delvare 2c003e8e1c i2c: Use put_user instead of copy_to_user where possible
This speeds up the I2C_FUNCS ioctl by 5 to 8% in my tests.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Laughed-at-by: Mark M. Hoffman <mhoffman@lightlink.com>
2006-12-10 21:21:30 +01:00
Josef Sipek cba0a12843 [PATCH] struct path: convert i2c-drivers
Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:45 -08:00
Greg Kroah-Hartman ac11d0601b I2C: convert i2c-dev to use struct device instead of struct class_device
As class_device is going away eventually...

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-01 14:51:59 -08:00
Jean Delvare b32d20dc8b i2c-dev: attach/detach_adapter cleanups
i2c-dev: attach/detach_adapter cleanups

* Only print that an adapter was attached when it succeeds.
* i2c_dev == NULL on detach simply means that the attach failed
  before, this isn't an error per se.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:51 -07:00