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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 12:52:02 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 12:52:02 -0800 |
commit | 0a1d4434db5f86c50018fe0aab299ac97dc15b76 (patch) | |
tree | 69574d3ef27cbf6527bcc38cd035d8bdf854203c /Documentation/RCU | |
parent | 79ad89123c2523a7982d457641dd64f339307e6c (diff) | |
parent | 18a207849218d8c15072f449e6d0b901262290c9 (diff) | |
download | lwn-0a1d4434db5f86c50018fe0aab299ac97dc15b76.tar.gz lwn-0a1d4434db5f86c50018fe0aab299ac97dc15b76.zip |
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
...
Diffstat (limited to 'Documentation/RCU')
-rw-r--r-- | Documentation/RCU/Design/Requirements/Requirements.rst | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst index a0f8164c8513..49387d823619 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.rst +++ b/Documentation/RCU/Design/Requirements/Requirements.rst @@ -1858,7 +1858,7 @@ unloaded. After a given module has been unloaded, any attempt to call one of its functions results in a segmentation fault. The module-unload functions must therefore cancel any delayed calls to loadable-module functions, for example, any outstanding mod_timer() must be dealt -with via del_timer_sync() or similar. +with via timer_shutdown_sync() or similar. Unfortunately, there is no way to cancel an RCU callback; once you invoke call_rcu(), the callback function is eventually going to be |