No description
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Tony Lindgren 6ba9a47d1f tty: n_gsm: Fix long delays with control frame timeouts in ADM mode
commit e9ec225479 upstream.

Commit ea3d8465ab ("tty: n_gsm: Allow ADM response in addition to UA for
control dlci") added support for DLCI to stay in Asynchronous Disconnected
Mode (ADM). But we still get long delays waiting for commands to other
DLCI to complete:

--> 5) C: SABM(P)
Q>  0) C: UIH(F)
Q>  0) C: UIH(F)
Q>  0) C: UIH(F)
...

This happens because gsm_control_send() sets cretries timer to T2 that is
by default set to 34. This will cause resend for T2 times for the control
frame. In ADM mode, we will never get a response so the control frame, so
retries are just delaying all the commands.

Let's fix the issue by setting DLCI_MODE_ADM flag after detecting the ADM
mode for the control DLCI. Then we can use that in gsm_control_send() to
set retries to 1. This means the control frame will be sent once allowing
the other end at an opportunity to switch from ADM to ABM mode.

Note that retries will be decremented in gsm_control_retransmit() so
we don't want to set it to 0 here.

Fixes: ea3d8465ab ("tty: n_gsm: Allow ADM response in addition to UA for control dlci")
Cc: linux-serial@vger.kernel.org
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jiri Prchal <jiri.prchal@aksignal.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russ Gorby <russ.gorby@intel.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-05-01 12:58:13 -07:00
arch s390/uprobes: implement arch_uretprobe_is_alive() 2018-04-29 11:33:18 +02:00
block blk-mq: fix discard merge with scheduler attached 2018-04-26 11:02:15 +02:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: aes-generic - build with -Os on gcc-7+ 2018-04-12 12:32:20 +02:00
Documentation s390: introduce CPU alternatives 2018-04-29 11:33:14 +02:00
drivers tty: n_gsm: Fix long delays with control frame timeouts in ADM mode 2018-05-01 12:58:13 -07:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs ext4: fix bitmap position validation 2018-05-01 12:58:07 -07:00
include tty: Don't call panic() at tty_ldisc_init() 2018-05-01 12:58:13 -07:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-24 09:36:23 +02:00
kernel tracing: Fix missing tab for hwlat_detector print format 2018-04-29 11:33:17 +02:00
lib bpf: fix selftests/bpf test_kmod.sh failure when CONFIG_BPF_JIT_ALWAYS_ON=y 2018-04-26 11:02:16 +02:00
mm mm/fadvise: discard partial page if endbyte is also EOF 2018-04-26 11:02:15 +02:00
net llc: fix NULL pointer deref for SOCK_ZAPPED 2018-04-29 11:33:13 +02:00
samples samples/bpf: Partially fixes the bpf.o build 2018-04-26 11:02:12 +02:00
scripts kconfig: Fix expr_free() E_NOT leak 2018-04-26 11:02:08 +02:00
security commoncap: Handle memory allocation failure. 2018-04-29 11:33:16 +02:00
sound ALSA: usb-audio: Skip broken EU on Dell dock USB-audio 2018-05-01 12:58:11 -07:00
tools perf test: Fix test trace+probe_libc_inet_pton.sh for s390x 2018-04-26 11:02:20 +02:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt kvm: Map PFN-type memory regions as writable (if possible) 2018-04-26 11:02:13 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.38 2018-04-29 11:33:18 +02:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.