Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a61 ("serial: do not accept sysrq characters via serial port")
At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.
As a measure of balance between on and off options, add
MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable
sysrq if it follows BREAK on a serial line. The longer the string - the
less likely it may be in the garbage.
Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.
Based-on-patch-by: Vasiliy Khoruzhick <vasilykh@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a61 ("serial: do not accept sysrq characters via serial port")
At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.
Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.
As a preparation to add sysrq_toggle_support() call into uart,
remove a private copy of sysrq_enabled from sysctl - it should reflect
the actual status of sysrq.
Furthermore, the private copy isn't correct already in case
sysrq_always_enabled is true. So, remove __sysrq_enabled and use a
getter-helper sysrq_mask() to check sysrq_key_op enabled status.
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-2-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e490c9144c ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal if data
is transmitted through the tty layer.
Console messages bypass the tty layer and instead are emitted via
serial8250_console_write(). Amend that function to drive RTS as well,
allowing for a console on rs485 ports.
Note that serial8250_console_write() may be called concurrently to the
tty layer accessing the port. The two protect their accesses with the
port lock, but serial8250_console_write() may find RTS still being
asserted by the tty layer, in which case it shouldn't be deasserted
after the console message has been printed. Recognize such situations
by checking the em485->tx_stopped flag.
If a delay_rts_before_send or delay_rts_after_send has been specified,
serial8250_console_write() busy-waits for its duration. Optimizations
for those wait times are conceivable: E.g. if RTS is already asserted,
we could check whether em485->start_tx_timer is active and wait only
for the remaining expire time. But this would require calling into
the hrtimer infrastructure, which involves acquiring locks and
potentially reprogramming timer hardware. Such operations seem too
risky in the context of console printout, which needs to work even when
the kernel has crashed and emits a BUG splat. So I've gone with a
simplistic solution which just always waits for the full delay.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/65edffce4670a19e598015c03cbe46f1ffd93e43.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Amend 8250_bcm2835aux.c to support rs485 as introduced for 8250_omap.c
by commit e490c9144c ("tty: Add software emulated RS485 support for
8250").
The bcm2835aux differs from omap chips by inverting the meaning of RTS
in the MCR register: If the bit is clear, RTS is high. With omap, it's
apparently the other way round.
Moreover, omap achieves half-duplex mode by disabling the UART_IER_RDI
interrupt and clearing the RX FIFO when TX stops. This approach doesn't
work on bcm2835aux because the UART_LSR_DR bit is set even when
UART_IER_RDI is disabled. Consequently, serial8250_handle_irq() invokes
serial8250_rx_chars() to empty the FIFO and characters are received even
though the user requested half-duplex. Solve by disabling the receiver
using the non-standard CNTL register.
Cache that register in the driver's private data for performance. Set
the private data pointer before calling serial8250_register_8250_port()
to prevent a null pointer deref in case one of the rs485 callbacks is
invoked immediately after port registration.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/dd86460e20a8f979b7272a0bde73640312b902b1.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e490c9144c ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
So far the only drivers taking advantage of it are 8250_omap.c and
8250_of.c.
We're about to make use of the feature in 8250_bcm2835aux.c as well.
The bcm2835aux differs from omap chips by inverting the meaning of RTS
in the MCR register. Moreover, omap achieves half-duplex mode by
disabling the RX interrupt and clearing the RX FIFO when TX stops.
The bcm2835aux requires disabling the receiver instead.
Support these behavioral differences by generalizing the rs485 emulation:
Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct
uart_8250_port, provide generic implementations containing the existing
code and use them as callbacks in 8250_omap.c and 8250_of.c.
start_tx_rs485() is idempotent in that it recognizes whether RTS is
already asserted. Achieve the same by introducing a tx_stopped flag in
struct uart_8250_em485. This may even perform a little better on arches
where memory access is faster than mmio access.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When rs485 transmission over an 8250 port stops, __stop_tx() assigns
active_timer = NULL before calling __stop_tx_rs485().
That function in turn either assigns active_timer = stop_tx_timer and
rearms the timer (in case a delay_rts_after_send needs to be observed)
or directly calls __do_stop_tx_rs485().
Move the assignment active_timer = NULL to __stop_tx_rs485() into the
branch which directly calls __do_stop_tx_rs485(), thereby avoiding a
duplicate assignment and simplifying the code.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/bca638405550eaf92f0c6060b553b687f35885e0.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Amend the generic ->rs485_config() callback to sanitize RTS polarity and
zero-fill the padding (in addition to the existing sanitization of the
RTS delays).
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/ff833721bc372d38678f289eb2a44dbf016d5203.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e490c9144c ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
Drivers opt in to the feature by calling serial8250_em485_init() from
their ->rs485_config() callback.
So far there are two drivers doing that, 8250_omap.c and 8250_of.c.
Both use an identical callback. We're about to add a third user of that
callback, therefore deduplicate it and move it to 8250_port.c.
Drivers now opt in to rs485 software emulation by assigning the generic
serial8250_rs485_config() callback introduced herein to their
.rs485_config struct member. This change allows unexporting
serial8250_em485_init() and declaring it static.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Cc: Heiko Schocher <hs@denx.de>
Link: https://lore.kernel.org/r/fcef63642dc4eae41ae7842d23747b2bf5d40285.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Retrieve rs485 devicetree properties on registration of 8250 ports in
case they are attached to an rs485 transceiver.
If the property "linux,rs485-enabled-at-boot-time" is present, invoke
the ->rs485_config() callback to immediately deassert RTS, thereby
ceasing control of the bus.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/5908ea89b7f9da54872d6634b606d83db032297a.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial8250_do_set_mctrl() currently allows modifying the RTS modem
control line even when RTS is used as an rs485 Transmit Enable signal.
It is thus possible for user space to interfere with rs485 communication
by invoking a TIOCMSET ioctl().
Ignore such change requests and retain the current RTS polarity when in
rs485 mode. Note that serial8250_set_mctrl() is always called with
port->lock held, so there's no risk that RTS is changed concurrently.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/b1ce34ca9bc4d7bdc6e9852fcf30b1f4e37c8a80.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a driver exposes early consoles with EARLYCON_DECLARE() and
OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it
by
earlycon=<driver>,<options>
The rationale behind this is that some drivers register multiple setup
functions under the same driver name. Eg.
OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);
It depends on the order of the entries which console_setup() actually
gets called. To make things worse, I guess it also depends on the
compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE()
ones.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200220174607.24285-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch corrects the SPDX License Identifier style in
header files related to tty serial drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).
Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Link: https://lore.kernel.org/r/20200301204517.GA10368@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the dependency with ARCH_SPRD from sprd serial/console Kconfig-s,
since we want them can be built-in when ARCH_SPRD is set as 'm'.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20200305103228.9686-2-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ->setup() callback is mandatory for the devices.
Provide it for Elkhart Lake UART ports.
Note, for time being it's empty, but in the future it might require
an additional configuration such as DMA.
Reported-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200305130822.36850-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MTK uart design no need to control uart clock,
so we just control bus clock in runtime function.
Add uart clock used count to avoid repeatedly switching the clock.
Signed-off-by: Changqi Hu <changqi.hu@mediatek.com>
Link: https://lore.kernel.org/r/1582707225-26815-1-git-send-email-changqi.hu@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The peripheral has support for inverting its input and/or output
signals. This is useful if the hardware flips polarity of the
peripheral's signal, such as swapped +/- pins on an RS-422 transceiver,
or an inverting level shifter. Add support for these control registers
via the device tree binding.
As part of this change, make the writes of the various registers more
uniform by moving the UCR3 block up near the other registers' blocks,
since the INVT bit must be set before enabling the peripheral.
Signed-off-by: George Hilliard <ghilliard@kopismobile.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20200226222319.18383-3-ghilliard@kopismobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Emulate half-duplex operation and use mctrl_gpio to add support for
RS485 tranceiver with transmit/receive switch hooked to RTS GPIO line.
This is needed to make use of the RS485 port found on Teltonika RUT955.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/20200221212331.GA21467@makrotopia.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The CPM UART (PowerPC) has an open coded GPIO modem control
handling. Since I can't test this I can't just migrate it to
the serial mctrl GPIO helper library though I wish I could.
I do second best and convert it to GPIO descriptors at least.
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200229231842.247563-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nothing in this driver uses the symbols from <linux/gpio.h>
so drop this include.
Cc: Rahul Tanwar <rahul.tanwar@linux.intel.com>
Cc: Songjun Wu <songjun.wu@linux.intel.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: John Crispin <john@phrozen.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200229212331.174946-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nothing in this driver uses the symbols from these GPIO
includes so drop them. These are probably just historical
artifacts from befor mctrl_gpio was used.
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Razvan Stefanescu <razvan.stefanescu@microchip.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200229220941.205599-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Shift the cases one level left as this is how we are supposed to write
the switch-case code according to the CodingStyle.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-9-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is declared in vt_kern.h, so no need to declare it in selection.c
which includes the header.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move all the selection global variables to a structure vc_selection,
instantiated as vc_sel. This helps to group all the variables together
and see what should be protected by the embedded lock too.
It might be used later also for per-console selection support.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
use_unicode needs not be global. It is used only in set_selection_kernel
and sel_pos (a callee). It is also always set there prior calling
sel_pos. So make use_unicode local and rename it to plain shorter
"unicode". Finally, propagate it to sel_pos via parameter.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
multiplier and mode are not actually needed:
* multiplier is used only in kmalloc_array, so use "use_unicode ? 4 : 1"
directly
* mode is used only to assign a bool in this manner:
if (cond)
x = true;
else
x = false;
So do "x = cond" directly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Variables declared in a switch statement before any case statements
cannot be automatically initialized with compiler instrumentation (as
they are not part of any execution flow). With GCC's proposed automatic
stack variable initialization feature, this triggers a warning (and they
don't get initialized). Clang's automatic stack variable initialization
(via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also
doesn't initialize such variables[1]. Note that these warnings (or silent
skipping) happen before the dead-store elimination optimization phase,
so even when the automatic initializations are later elided in favor of
direct initializations, the warnings remain.
To avoid these problems, move such variables into the "case" where
they're used or lift them up into the main function body.
drivers/tty/n_tty.c: In function ‘__process_echoes’:
drivers/tty/n_tty.c:657:18: warning: statement will never be executed [-Wswitch-unreachable]
657 | unsigned int num_chars, num_bs;
| ^~~~~~~~~
[1] https://bugs.llvm.org/show_bug.cgi?id=44916
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200220062313.69209-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
These two were macros. Switch them to static inlines, so that it's more
understandable what they are doing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Do
s@[ \t]\+$@@
s@ \+\t@\t@
on the file as there are many spaces at the begininning of lines and
many spaces/tabs at EOLs. And vim screamed.
git show -w is supposed to show no difference here.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-20-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* we mark the message in n_hdlc_tty_receive as error
* we use __func__ instead of explicit function name
* we switch the remaining prints to pr_* helpers
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-19-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY_NO_WRITE_SPLIT is (always) defined in linux/tty.h, so no need to
check for it.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-18-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
They are in fact bools, so save some bytes (8B on x86_64). Also describe
@woke_up as we know what it is.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-17-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Given both rx and tx allocations do the same, add a new helper
(n_hdlc_alloc_buf) and use it for both of them. This cleans up
n_hdlc_alloc slightly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-15-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We got rid of backup_tty recently. Also, the tty layer ensures not to
call other ldisc hooks after ldisc close. That means, all those tests
are superfluous now so remove them.
Note that we remove the magic check in write after schedule too. The tty
cannot change during schedule.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-14-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's not needed, as now it's clear, that it's always the same as the one
passed from the tty layer.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Put the body of n_hdlc_release into the only caller. It can be seen,
that the "if" is superfluous now -- the same happens few lines above in
n_hdlc_tty_close already. So drop it.
Drop also n_hdlc2tty macro as this was the only user.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-12-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's simple tty->disc_data, but it obfuscates code. So expand it to all
locations and drop it.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-11-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This makes the functions return immediatelly on invalid state. And we
can push the indent of the later code one level left.
Pass "-w" to "git show" to see we are changing only the conditions (and
whitespace).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_hdlc_release contains four loops to free each buffer list. Create a
helper (n_hdlc_free_buf_list) and call it for every list instead. It
makes n_hdlc_release more readable.
We are switching from "for (;;)" to "do {} while (buf)" which avoids the
"if (buf)" completely -- kfree is a nop for NULL pointers.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is easier to read. And use MAX_HDLC_FRAME_SIZE instead of magic
constant.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
