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12 commits

Author SHA1 Message Date
Xie He
65d2dbb300 net: lapb: Make "lapb_t1timer_running" able to detect an already running timer
Problem:

The "lapb_t1timer_running" function in "lapb_timer.c" is used in only
one place: in the "lapb_kick" function in "lapb_out.c". "lapb_kick" calls
"lapb_t1timer_running" to check if the timer is already pending, and if
it is not, schedule it to run.

However, if the timer has already fired and is running, and is waiting to
get the "lapb->lock" lock, "lapb_t1timer_running" will not detect this,
and "lapb_kick" will then schedule a new timer. The old timer will then
abort when it sees a new timer pending.

I think this is not right. The purpose of "lapb_kick" should be ensuring
that the actual work of the timer function is scheduled to be done.
If the timer function is already running but waiting for the lock,
"lapb_kick" should not abort and reschedule it.

Changes made:

I added a new field "t1timer_running" in "struct lapb_cb" for
"lapb_t1timer_running" to use. "t1timer_running" will accurately reflect
whether the actual work of the timer is pending. If the timer has fired
but is still waiting for the lock, "t1timer_running" will still correctly
reflect whether the actual work is waiting to be done.

The old "t1timer_stop" field, whose only responsibility is to ask a timer
(that is already running but waiting for the lock) to abort, is no longer
needed, because the new "t1timer_running" field can fully take over its
responsibility. Therefore "t1timer_stop" is deleted.

"t1timer_running" is not simply a negation of the old "t1timer_stop".
At the end of the timer function, if it does not reschedule itself,
"t1timer_running" is set to false to indicate that the timer is stopped.

For consistency of the code, I also added "t2timer_running" and deleted
"t2timer_stop".

Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-23 14:14:50 -07:00
Xie He
b491e6a739 net: lapb: Add locking to the lapb module
In the lapb module, the timers may run concurrently with other code in
this module, and there is currently no locking to prevent the code from
racing on "struct lapb_cb". This patch adds locking to prevent racing.

1. Add "spinlock_t lock" to "struct lapb_cb"; Add "spin_lock_bh" and
"spin_unlock_bh" to APIs, timer functions and notifier functions.

2. Add "bool t1timer_stop, t2timer_stop" to "struct lapb_cb" to make us
able to ask running timers to abort; Modify "lapb_stop_t1timer" and
"lapb_stop_t2timer" to make them able to abort running timers;
Modify "lapb_t2timer_expiry" and "lapb_t1timer_expiry" to make them
abort after they are stopped by "lapb_stop_t1timer", "lapb_stop_t2timer",
and "lapb_start_t1timer", "lapb_start_t2timer".

3. Let lapb_unregister wait for other API functions and running timers
to stop.

4. The lapb_device_event function calls lapb_disconnect_request. In
order to avoid trying to hold the lock twice, add a new function named
"__lapb_disconnect_request" which assumes the lock is held, and make
it called by lapb_disconnect_request and lapb_device_event.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20210126040939.69995-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-26 17:53:45 -08:00
Martin Schiller
62480b992b net/lapb: fix t1 timer handling for LAPB_STATE_0
1. DTE interface changes immediately to LAPB_STATE_1 and start sending
   SABM(E).

2. DCE interface sends N2-times DM and changes to LAPB_STATE_1
   afterwards if there is no response in the meantime.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-27 17:22:51 -08:00
Thomas Gleixner
ee5d8f4d89 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 41
Based on 1 normalized pattern(s):

  this module is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:12 +02:00
Kees Cook
841b86f328 treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts
With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:

    perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
        $(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)

    perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
        $(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)

The now unused macros are also dropped from include/linux/timer.h.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-21 16:35:54 -08:00
Kees Cook
83a37b3292 net/lapb: Convert timers to use timer_setup()
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: linux-x25@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 12:39:36 +01:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
josselin.costanzi@mobile-devices.fr
a224bd36bf net/lapb: re-send packets on timeout
Actually re-send packets when the T1 timer runs out. This fixes a bug
where packets are waiting on the write queue until disconnection when
no other traffic is outstanding.

Signed-off-by: Josselin Costanzi <josselin.costanzi@mobile-devices.fr>
Signed-off-by: Maxime Jayat <maxime.jayat@mobile-devices.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-23 16:52:45 -04:00
Joe Perches
a508da6cc0 lapb: Neaten debugging
Enable dynamic debugging and remove a bunch of #ifdef/#endifs.

Add a lapb_dbg(level, fmt, ...) macro and replace the
printk(KERN_DEBUG uses.
Add pr_fmt and remove embedded prefixes.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-17 18:45:20 -04:00
David Howells
9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
YOSHIFUJI Hideaki
56d6c3d7a7 [NET] LAPB: Fix whitespace errors.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-10 23:19:51 -08:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00