net: lapb: Use list_for_each_entry() to simplify code in lapb_iface.c

Convert list_for_each() to list_for_each_entry() where
applicable. This simplifies the code.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

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: 1da177e4c3f4 ("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>

net: lapb: Decrease the refcount of "struct lapb_cb" in lapb_device_event

In lapb_device_event, lapb_devtostruct is called to get a reference to
an object of "struct lapb_cb". lapb_devtostruct increases the refcount
of the object and returns a pointer to it. However, we didn't decrease
the refcount after we finished using the pointer. This patch fixes this
problem.

Fixes: a4989fa91110 ("net/lapb: support netdev events")
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201231174331.64539-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/lapb: support netdev events

This patch allows layer2 (LAPB) to react to netdev events itself and
avoids the detour via layer3 (X.25).

1. Establish layer2 on NETDEV_UP events, if the carrier is already up.

2. Call lapb_disconnect_request() on NETDEV_GOING_DOWN events to signal
the peer that the connection will go down.
(Only when the carrier is up.)

3. When a NETDEV_DOWN event occur, clear all queues, enter state
LAPB_STATE_0 and stop all timers.

4. The NETDEV_CHANGE event makes it possible to handle carrier loss and
detection.

In case of Carrier Loss, clear all queues, enter state LAPB_STATE_0
and stop all timers.

In case of Carrier Detection, we start timer t1 on a DCE interface,
and on a DTE interface we change to state LAPB_STATE_1 and start
sending SABM(E).

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Acked-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

lapb: fixed leak of control-blocks.

lapb_register calls lapb_create_cb, which initializes the control-
block's ref-count to one, and __lapb_insert_cb, which increments it when
adding the new block to the list of blocks.

lapb_unregister calls __lapb_remove_cb, which decrements the ref-count
when removing control-block from the list of blocks, and calls lapb_put
itself to decrement the ref-count before returning.

However, lapb_unregister also calls __lapb_devtostruct to look up the
right control-block for the given net_device, and __lapb_devtostruct
also bumps the ref-count, which means that when lapb_unregister returns
the ref-count is still 1 and the control-block is leaked.

Call lapb_put after __lapb_devtostruct to fix leak.

Reported-by: syzbot+afb980676c836b4a0afa@syzkaller.appspotmail.com
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

lapb: moved export of lapb_register.

The EXPORT_SYMBOL for lapb_register was next to a different function.
Moved it to the right place.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

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>

net, lapb: convert lapb_cb.refcnt from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

lapb: move EXPORT_SYMBOL after functions.

See Documentation/CodingStyle Chapter 6

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

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>

wan: make LAPB callbacks const

This is compile tested only.
Suggested by dumpster diving in PAX.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

lapb: Reduce switch/case indent

Make the case labels the same indent as the switch.

git diff -w shows 80 column reflowing.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

net: remove NET_RX_BAD and NET_RX_CN* defines

almost no users in the tree; and the few that use them treat them
like NET_RX_DROP.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

[LAPB] net/lapb/lapb_iface.c: use LIST_HEAD instead of LIST_HEAD_INIT

single list_head variable initialized with LIST_HEAD_INIT could almost
always can be replaced with LIST_HEAD declaration, this shrinks the code
and looks better.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET] LAPB: Fix whitespace errors.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[LAPB]: Fix windowsize check

In bug #6954, Norbert Reinartz reported the following issue:

"Function lapb_setparms() in file net/lapb/lapb_iface.c checks if the given
parameters are valid. If the given window size is in the range of 8 .. 127,
lapb_setparms() fails and returns an error value of LAPB_INVALUE, even if bit
LAPB_EXTENDED in parms->mode is set.
If bit LAPB_EXTENDED in parms->mode is set and the window size is in the range
of 8 .. 127, the first check "(parms->mode & LAPB_EXTENDED)" results true and
the second check "(parms->window < 1 || parms->window > 127)" results false.
Both checks in conjunction result to false, thus the third check "(parms->window
< 1 || parms->window > 7)" is done by fault.
This third check results true, so that we leave lapb_setparms() by 'goto out_put'.
Seems that this bug doesn't cause any problems, because lapb_setparms() isn't
used to change the default values of LAPB. We are using kernel lapb in our
software project and also change the default parameters of lapb, so we found
this bug"

He also pasted a fix, that I've transformated into a patch:

Signed-off-by: Diego Calleja <diegocg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Conversions from kmalloc+memset to k(z|c)alloc.

Signed-off-by: Panagiotis Issaris <takis@issaris.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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!