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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
arch Merge git://git.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2021-03-09 17:15:56 -08:00
block block/bfq: update comments and default value in docs for fifo_expire 2021-03-02 11:25:38 -07:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-08 11:52:17 +01:00
Documentation dt-bindings: net: dsa: lantiq: add xRx300 and xRX330 switch bindings 2021-03-22 16:33:39 -07:00
drivers net: dsa: hellcreek: Report switch name and ID 2021-03-22 18:02:10 -07:00
fs pstore fixes for v5.12-rc2 2021-03-05 17:21:25 -08:00
include net: lapb: Make "lapb_t1timer_running" able to detect an already running timer 2021-03-23 14:14:50 -07:00
init Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-03-09 18:07:05 -08:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-03-09 18:07:05 -08:00
lib Merge git://git.kernel.org:/pub/scm/linux/kernel/git/davem/sparc 2021-03-08 22:01:58 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm swap: fix swapfile read/write offset 2021-03-02 17:25:46 -07:00
net net: lapb: Make "lapb_t1timer_running" able to detect an already running timer 2021-03-23 14:14:50 -07:00
samples samples: pktgen: new append mode 2021-03-14 14:22:38 -07:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-03-09 18:07:05 -08:00
security nexthop: Add netlink defines and enumerators for resilient NH groups 2021-03-11 16:12:59 -08:00
sound ALSA: hda/realtek: Apply dual codec quirks for MSI Godlike X570 board 2021-03-03 15:25:03 +01:00
tools selftests: net: forwarding: Fix a typo 2021-03-18 20:38:48 -07:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Add entries for Actions Semi Owl Ethernet MAC 2021-03-22 12:56:21 -07:00
Makefile Linux 5.12-rc2 2021-03-05 17:33:41 -08:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.