WSL2-Linux-Kernel/Documentation/RCU
Linus Torvalds 0a1d4434db Updates for timers, timekeeping and drivers:
- Core:
 
    - The timer_shutdown[_sync]() infrastructure:
 
      Tearing down timers can be tedious when there are circular
      dependencies to other things which need to be torn down. A prime
      example is timer and workqueue where the timer schedules work and the
      work arms the timer.
 
      What needs to prevented is that pending work which is drained via
      destroy_workqueue() does not rearm the previously shutdown
      timer. Nothing in that shutdown sequence relies on the timer being
      functional.
 
      The conclusion was that the semantics of timer_shutdown_sync() should
      be:
 
 	- timer is not enqueued
     	- timer callback is not running
     	- timer cannot be rearmed
 
      Preventing the rearming of shutdown timers is done by discarding rearm
      attempts silently. A warning for the case that a rearm attempt of a
      shutdown timer is detected would not be really helpful because it's
      entirely unclear how it should be acted upon. The only way to address
      such a case is to add 'if (in_shutdown)' conditionals all over the
      place. This is error prone and in most cases of teardown not required
      all.
 
    - The real fix for the bluetooth HCI teardown based on
      timer_shutdown_sync().
 
      A larger scale conversion to timer_shutdown_sync() is work in
      progress.
 
    - Consolidation of VDSO time namespace helper functions
 
    - Small fixes for timer and timerqueue
 
  - Drivers:
 
    - Prevent integer overflow on the XGene-1 TVAL register which causes
      an never ending interrupt storm.
 
    - The usual set of new device tree bindings
 
    - Small fixes and improvements all over the place
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Merge tag 'timers-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "Updates for timers, timekeeping and drivers:

  Core:

   - The timer_shutdown[_sync]() infrastructure:

     Tearing down timers can be tedious when there are circular
     dependencies to other things which need to be torn down. A prime
     example is timer and workqueue where the timer schedules work and
     the work arms the timer.

     What needs to prevented is that pending work which is drained via
     destroy_workqueue() does not rearm the previously shutdown timer.
     Nothing in that shutdown sequence relies on the timer being
     functional.

     The conclusion was that the semantics of timer_shutdown_sync()
     should be:
	- timer is not enqueued
    	- timer callback is not running
    	- timer cannot be rearmed

     Preventing the rearming of shutdown timers is done by discarding
     rearm attempts silently.

     A warning for the case that a rearm attempt of a shutdown timer is
     detected would not be really helpful because it's entirely unclear
     how it should be acted upon. The only way to address such a case is
     to add 'if (in_shutdown)' conditionals all over the place. This is
     error prone and in most cases of teardown not required all.

   - The real fix for the bluetooth HCI teardown based on
     timer_shutdown_sync().

     A larger scale conversion to timer_shutdown_sync() is work in
     progress.

   - Consolidation of VDSO time namespace helper functions

   - Small fixes for timer and timerqueue

  Drivers:

   - Prevent integer overflow on the XGene-1 TVAL register which causes
     an never ending interrupt storm.

   - The usual set of new device tree bindings

   - Small fixes and improvements all over the place"

* tag 'timers-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  dt-bindings: timer: renesas,cmt: Add r8a779g0 CMT support
  dt-bindings: timer: renesas,tmu: Add r8a779g0 support
  clocksource/drivers/arm_arch_timer: Use kstrtobool() instead of strtobool()
  clocksource/drivers/timer-ti-dm: Fix missing clk_disable_unprepare in dmtimer_systimer_init_clock()
  clocksource/drivers/timer-ti-dm: Clear settings on probe and free
  clocksource/drivers/timer-ti-dm: Make timer_get_irq static
  clocksource/drivers/timer-ti-dm: Fix warning for omap_timer_match
  clocksource/drivers/arm_arch_timer: Fix XGene-1 TVAL register math error
  clocksource/drivers/timer-npcm7xx: Enable timer 1 clock before use
  dt-bindings: timer: nuvoton,npcm7xx-timer: Allow specifying all clocks
  dt-bindings: timer: rockchip: Add rockchip,rk3128-timer
  clockevents: Repair kernel-doc for clockevent_delta2ns()
  clocksource/drivers/ingenic-ost: Define pm functions properly in platform_driver struct
  clocksource/drivers/sh_cmt: Access registers according to spec
  vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy
  Bluetooth: hci_qca: Fix the teardown problem for real
  timers: Update the documentation to reflect on the new timer_shutdown() API
  timers: Provide timer_shutdown[_sync]()
  timers: Add shutdown mechanism to the internal functions
  timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode
  ...
2022-12-12 12:52:02 -08:00
..
Design timers: Update the documentation to reflect on the new timer_shutdown() API 2022-11-24 15:09:12 +01:00
NMI-RCU.rst drivers: Remove CONFIG_OPROFILE support 2021-01-29 10:06:24 +05:30
RTFP.txt docs: Correctly spell Stephen Hemminger's name 2021-03-15 13:53:24 -07:00
UP.rst doc: RCU callback locks need only _bh, not necessarily _irq 2019-06-28 09:10:40 -06:00
checklist.rst doc: Update checklist.txt 2022-10-18 14:58:50 -07:00
index.rst doc: Remove arrayRCU.rst 2022-10-18 14:58:50 -07:00
listRCU.rst doc: Update listRCU.rst 2022-10-20 11:57:19 -07:00
lockdep-splat.rst docs: RCU: Convert lockdep-splat.txt to ReST 2020-06-29 11:58:10 -07:00
lockdep.rst doc: Update RCU's lockdep.rst 2022-10-20 11:57:46 -07:00
rcu.rst docs: Update RCU cross-references as suggested in doc-guide 2022-04-20 16:13:52 -07:00
rcu_dereference.rst doc: Update rcu_access_pointer() advice in rcu_dereference.rst 2022-08-31 04:58:15 -07:00
rcubarrier.rst doc: Use CONFIG_PREEMPTION 2021-01-06 16:10:44 -08:00
rculist_nulls.rst docs: Update RCU cross-references as suggested in doc-guide 2022-04-20 16:13:52 -07:00
rcuref.rst docs: RCU: Convert rcuref.txt to ReST 2020-06-29 11:58:11 -07:00
stallwarn.rst rcu/context-tracking: Remove unused and/or unecessary middle functions 2022-07-05 13:33:00 -07:00
torture.rst docs: RCU: Convert torture.txt to ReST 2020-06-29 11:58:11 -07:00
whatisRCU.rst doc/rcu: Update LWN article URLs and add 2019 article 2022-08-31 04:58:15 -07:00