isdn: document Kernel CAPI driver interface

Create a file Documentation/isdn/INTERFACE.CAPI describing the
interface between the kernel CAPI subsystem and ISDN device drivers,
analogous to the existing Documentation/isdn/INTERFACE for the old
isdn4linux subsystem. Also add kerneldoc comments to the exported
functions in drivers/isdn/capi/kcapi.c.

Impact: Documentation
Signed-off-by: NTilman Schmidt <tilman@imap.cc>
Signed-off-by: NKarsten Keil <keil@b1-systems.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

struct tty_operations::proc_fops took it's place and there is one less
create_proc_read_entry() user now!
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: Attribute functions with __acquires(...) resp. __releases(...).

Fix this sparse warnings:
  drivers/isdn/capi/kcapi_proc.c:241:13: warning: context imbalance in 'capi_driver_start' - wrong count at exit
  drivers/isdn/capi/kcapi_proc.c:252:13: warning: context imbalance in 'capi_driver_stop' - unexpected unlock
Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove some pointless conditionals before kfree_skb().
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Correct two typos.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Cc: isdn4linux@listserv.isdn4linux.de
Signed-off-by: NJames Morris <jmorris@namei.org>

Now that device_create() has been audited, rename things back to the
original call to be sane.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Today's linux-next build (x86_64 allmodconfig) failed like this:

/drivers/char/tty_ioctl.c: In function 'change_termios':
drivers/isdn/capi/capi.c:1234: error: implicit declaration of function 'n_tty_ioctl'
drivers/isdn/gigaset/ser-gigaset.c: In function 'gigaset_tty_ioctl':
drivers/isdn/gigaset/ser-gigaset.c:648: error: implicit declaration of function 'n_tty_ioctl'

Introduced by commit 686b5e4aea05a80e370dc931b7f4a8d03c80da54
("tty-move-canon-specials").  I added the following patch (which may not
be correct).
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After calling capi_ctr_get, error handling code should call capi_ctr_put.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r@
expression x,E;
statement S;
position p1,p2,p3;
@@

(
if ((x = capi_ctr_get@p1(...)) == NULL || ...) S
|
x = capi_ctr_get@p1(...)
... when != x
if (x == NULL || ...) S
)
<...
if@p3 (...) { ... when != capi_ctr_put(x)
                  when != if (x) { ... capi_ctr_put(x); ...}
    return@p2 ...;
}
...>
(
return x;
|
return 0;
|
x = E
|
E = x
|
capi_ctr_put(x)
)

@exists@
position r.p1,r.p2,r.p3;
expression x;
int ret != 0;
statement S;
@@

* x = capi_ctr_get@p1(...)
  <...
* if@p3 (...)
  S
  ...>
* return@p2 \(NULL\|ret\);
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

device_create() is race-prone, so use the race-free
device_create_drvdata() instead as device_create() is going away.

Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move the line disciplines towards a conventional ->ops arrangement.  For
the moment the actual 'tty_ldisc' struct in the tty is kept as part of
the tty struct but this can then be changed if it turns out that when it
all settles down we want to refcount ldiscs separately to the tty.

Pull the ldisc code out of /proc and put it with our ldisc code.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Put explicit lock_kernel() calls into capi_open()
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

cdebug_init() is called from kcapi_init() which is module
initialization function, so it must return negative values on errors.
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAlan Cox <alan@redhat.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use proc_create()/proc_create_data() to make sure that ->proc_fops and ->data
be setup before gluing PDE to main tree.

Add correct ->owner to proc_fops to fix reading/module unloading race.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Acked-by: NKarsten Keil <kkeil@suse.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since CONFIG_AVMB1_COMPAT is not a Kconfig variable, move it out of the
Kconfig namespace.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

capifs_remount may reach 'return' statement without freeing of memory
allocated by kstrdup call
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/isdn/capi/kcapi.c:829:30: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:838:27: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:954:17: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:1007:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/kcapi.c:1009:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capiutil.c:453:24: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capilib.c:47:30: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:353:29: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:369:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:486:48: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:515:46: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:541:47: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:692:47: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:699:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:704:14: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:943:53: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:948:32: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:969:42: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:989:48: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1026:69: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1028:19: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1061:20: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1529:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capi.c:1531:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:338:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:758:32: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:880:40: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:407:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:407:15: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:444:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:429:49: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:1664:61: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:1969:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2294:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2297:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2338:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capidrv.c:2341:33: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capifs.c:192:37: warning: Using plain integer as NULL pointer
drivers/isdn/capi/capifs.c:194:33: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a .show_options super operation to capifs.

Use generic_show_options() and save the complete option string in
capifs_remount().
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix overwriting the stack with the version string
(it is currently 10 bytes + zero) when unloading the
capidrv module. Safeguard against overwriting it
should the version string grow in the future.

Should fix Kernel Bug Tracker Bug 9696.
Signed-off-by: NGerd v. Egidy <gerd.von.egidy@intra2net.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NTony Jones <tonyj@suse.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

* change #warning to a code comment

* add comment and special ifdef'd 64-bit code for a situation where
  we must store a pointer into a CAPI field 'Data', which is fixed by
  the interface at 32 bits.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NKarsten Keil <kkeil@suse.de>

In drivers/isdn/capi/kcapi.c::old_capi_manufacturer(), if the call to
get_capi_ctr_by_nr(ldef.contr); in line 823 returns NULL, then we'll be
dereferencing a NULL pointer in the very next line.

(Found by Coverity checker as bug #402)
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If we fail to allocate an skb in
drivers/isdn/capi/capidrv.c::send_message(), then we'll end up
dereferencing a NULL pointer.
Since out of memory conditions are not unheard of, I believe it
is better to print a error message and just return rather than
bring down the whole kernel.
Sure, doing this may upset some application, but that's still
better than crashing the whole system.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/isdn/capi/capi.c: In function 'handle_minor_send':
drivers/isdn/capi/capi.c:552: warning: cast from pointer to integer of different size

Of course, the code here might actually be buggy, in which case this patch
should not be applied?

Answer:

  No this field is ignored inside linux kernel.Yes this is ugly, but it's
  the CAPI spec for all OS.

  CAPI DATA_B3 Request/Indication CAPI Message has a mandatory field which
  represent the 32 bit buffer address of the payload data.  In linux the
  payload data do not use a sperate buffer, data follows directely after the
  CAPI Message in the same skb and we use this assumption inside the drivers,
  so we can ignore this field.

  Inside the linux CAPI implemetation we never use this field, so it could
  also have no value, but since random data in a message is bad as well (e.g.
  displayed in CAPI traces) we set is to the most adequate value.

  Outside the kernel the capi20 library sets the correct addresses (there is
  an optional second field for 64 bit adresses for 64 bit systems, we do not
  use here).
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Transform "depends on" into a simpler if-endif block style dependency.
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The similar code exists here and is called capi_driver_get_idx().  Use generic
helpers now and remember to convert list_head to struct capi_driver in .show
callback.
Signed-off-by: NPavel Emelianov <xemul@openvz.org>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The CAPI 2.0 driver uses a semaphore as mutex.  Use the mutex API instead of
the (binary) semaphore.
Signed-off-by: NMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix various typos in kernel docs and Kconfigs, 2.6.21-rc4.
Signed-off-by: NMatt LaPlante <kernel1@cyberdogtech.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

The CAPI 2.0 interface uses a semaphore as mutex.  Use the mutex API instead
of the (binary) semaphore.
Signed-off-by: NMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The CAPI trace debug functions were using a fixed size buffer, which can be
overflowed if wrong formatted CAPI messages were sent to the kernel capi
layer.  The code was also not protected against multiple callers.  This fix
bug 8028.

Additionally the patch make the CAPI trace functions optional.
Signed-off-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: NTim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I think the following patch should go into the kernel, until the ISDN/CAPI
guys create the real fix for this issue.

The issue is a concurrency issue with some internal CAPI data structure
which can crash the kernel.

On my FritzCard DSL with the AVM driver it crashes about once a day without
this workaround patch.  With this workaround patch it's rock-stable (at
least on UP, but I don't see why this shouldn't work on SMP as well.  But
maybe I'm missing something.)

This workaround is kind of a sledgehammer which inserts a global lock to
wrap around all the critical sections.  Of course, this is a scalability
issue, if you have many ISDN/CAPI cards.  But it prevents a crash.  So I
vote for this fix to get merged, until people come up with a better
solution.  Better have a stable kernel that's less scalable, than a
crashing and useless kernel.

This bug is in the kernel since 2.6.15 (at least).
Signed-off-by: NMichael Buesch <mb@bu3sch.de>
Cc: Kai Germaschewski <kai.germaschewski@gmx.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAhmed S. Darwish <darwish.07@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>