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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 23:52:02 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 23:52:02 +0300 |
commit | 0a1d4434db5f86c50018fe0aab299ac97dc15b76 (patch) | |
tree | 69574d3ef27cbf6527bcc38cd035d8bdf854203c /Documentation | |
parent | 79ad89123c2523a7982d457641dd64f339307e6c (diff) | |
parent | 18a207849218d8c15072f449e6d0b901262290c9 (diff) | |
download | linux-0a1d4434db5f86c50018fe0aab299ac97dc15b76.tar.xz |
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')
10 files changed, 31 insertions, 20 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 diff --git a/Documentation/core-api/local_ops.rst b/Documentation/core-api/local_ops.rst index 2ac3f9f29845..0b42ceaaf3c4 100644 --- a/Documentation/core-api/local_ops.rst +++ b/Documentation/core-api/local_ops.rst @@ -191,7 +191,7 @@ Here is a sample module which implements a basic per cpu counter using static void __exit test_exit(void) { - del_timer_sync(&test_timer); + timer_shutdown_sync(&test_timer); } module_init(test_init); diff --git a/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml b/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml index 737af78ad70c..d53e1bb98b8a 100644 --- a/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml +++ b/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml @@ -25,7 +25,13 @@ properties: - description: The timer interrupt of timer 0 clocks: - maxItems: 1 + items: + - description: The reference clock for timer 0 + - description: The reference clock for timer 1 + - description: The reference clock for timer 2 + - description: The reference clock for timer 3 + - description: The reference clock for timer 4 + minItems: 1 required: - compatible diff --git a/Documentation/devicetree/bindings/timer/renesas,cmt.yaml b/Documentation/devicetree/bindings/timer/renesas,cmt.yaml index bde6c9b66bf4..a0be1755ea28 100644 --- a/Documentation/devicetree/bindings/timer/renesas,cmt.yaml +++ b/Documentation/devicetree/bindings/timer/renesas,cmt.yaml @@ -102,12 +102,14 @@ properties: - enum: - renesas,r8a779a0-cmt0 # 32-bit CMT0 on R-Car V3U - renesas,r8a779f0-cmt0 # 32-bit CMT0 on R-Car S4-8 + - renesas,r8a779g0-cmt0 # 32-bit CMT0 on R-Car V4H - const: renesas,rcar-gen4-cmt0 # 32-bit CMT0 on R-Car Gen4 - items: - enum: - renesas,r8a779a0-cmt1 # 48-bit CMT on R-Car V3U - renesas,r8a779f0-cmt1 # 48-bit CMT on R-Car S4-8 + - renesas,r8a779g0-cmt1 # 48-bit CMT on R-Car V4H - const: renesas,rcar-gen4-cmt1 # 48-bit CMT on R-Car Gen4 reg: diff --git a/Documentation/devicetree/bindings/timer/renesas,tmu.yaml b/Documentation/devicetree/bindings/timer/renesas,tmu.yaml index 60f4c059bcff..a67e427a9e7e 100644 --- a/Documentation/devicetree/bindings/timer/renesas,tmu.yaml +++ b/Documentation/devicetree/bindings/timer/renesas,tmu.yaml @@ -38,6 +38,7 @@ properties: - renesas,tmu-r8a77995 # R-Car D3 - renesas,tmu-r8a779a0 # R-Car V3U - renesas,tmu-r8a779f0 # R-Car S4-8 + - renesas,tmu-r8a779g0 # R-Car V4H - const: renesas,tmu reg: diff --git a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml index dc3bc1e62fe9..b61ed1a431bb 100644 --- a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml +++ b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml @@ -18,6 +18,7 @@ properties: - enum: - rockchip,rv1108-timer - rockchip,rk3036-timer + - rockchip,rk3128-timer - rockchip,rk3188-timer - rockchip,rk3228-timer - rockchip,rk3229-timer diff --git a/Documentation/kernel-hacking/locking.rst b/Documentation/kernel-hacking/locking.rst index 6805ae6e86e6..c756786e17ae 100644 --- a/Documentation/kernel-hacking/locking.rst +++ b/Documentation/kernel-hacking/locking.rst @@ -967,7 +967,7 @@ you might do the following:: while (list) { struct foo *next = list->next; - del_timer(&list->timer); + timer_delete(&list->timer); kfree(list); list = next; } @@ -981,7 +981,7 @@ the lock after we spin_unlock_bh(), and then try to free the element (which has already been freed!). This can be avoided by checking the result of -del_timer(): if it returns 1, the timer has been deleted. +timer_delete(): if it returns 1, the timer has been deleted. If 0, it means (in this case) that it is currently running, so we can do:: @@ -990,7 +990,7 @@ do:: while (list) { struct foo *next = list->next; - if (!del_timer(&list->timer)) { + if (!timer_delete(&list->timer)) { /* Give timer a chance to delete this */ spin_unlock_bh(&list_lock); goto retry; @@ -1005,9 +1005,12 @@ do:: Another common problem is deleting timers which restart themselves (by calling add_timer() at the end of their timer function). Because this is a fairly common case which is prone to races, you should -use del_timer_sync() (``include/linux/timer.h``) to -handle this case. It returns the number of times the timer had to be -deleted before we finally stopped it from adding itself back in. +use timer_delete_sync() (``include/linux/timer.h``) to handle this case. + +Before freeing a timer, timer_shutdown() or timer_shutdown_sync() should be +called which will keep it from being rearmed. Any subsequent attempt to +rearm the timer will be silently ignored by the core code. + Locking Speed ============= @@ -1335,7 +1338,7 @@ lock. - kfree() -- add_timer() and del_timer() +- add_timer() and timer_delete() Mutex API reference =================== diff --git a/Documentation/timers/hrtimers.rst b/Documentation/timers/hrtimers.rst index c1c20a693e8f..7ac448908d1f 100644 --- a/Documentation/timers/hrtimers.rst +++ b/Documentation/timers/hrtimers.rst @@ -118,7 +118,7 @@ existing timer wheel code, as it is mature and well suited. Sharing code was not really a win, due to the different data structures. Also, the hrtimer functions now have clearer behavior and clearer names - such as hrtimer_try_to_cancel() and hrtimer_cancel() [which are roughly -equivalent to del_timer() and del_timer_sync()] - so there's no direct +equivalent to timer_delete() and timer_delete_sync()] - so there's no direct 1:1 mapping between them on the algorithmic level, and thus no real potential for code sharing either. diff --git a/Documentation/translations/it_IT/kernel-hacking/locking.rst b/Documentation/translations/it_IT/kernel-hacking/locking.rst index 51af37f2d621..b8ecf41273c5 100644 --- a/Documentation/translations/it_IT/kernel-hacking/locking.rst +++ b/Documentation/translations/it_IT/kernel-hacking/locking.rst @@ -990,7 +990,7 @@ potreste fare come segue:: while (list) { struct foo *next = list->next; - del_timer(&list->timer); + timer_delete(&list->timer); kfree(list); list = next; } @@ -1003,7 +1003,7 @@ e prenderà il *lock* solo dopo spin_unlock_bh(), e cercherà di eliminare il suo oggetto (che però è già stato eliminato). Questo può essere evitato controllando il valore di ritorno di -del_timer(): se ritorna 1, il temporizzatore è stato già +timer_delete(): se ritorna 1, il temporizzatore è stato già rimosso. Se 0, significa (in questo caso) che il temporizzatore è in esecuzione, quindi possiamo fare come segue:: @@ -1012,7 +1012,7 @@ esecuzione, quindi possiamo fare come segue:: while (list) { struct foo *next = list->next; - if (!del_timer(&list->timer)) { + if (!timer_delete(&list->timer)) { /* Give timer a chance to delete this */ spin_unlock_bh(&list_lock); goto retry; @@ -1026,10 +1026,8 @@ esecuzione, quindi possiamo fare come segue:: Un altro problema è l'eliminazione dei temporizzatori che si riavviano da soli (chiamando add_timer() alla fine della loro esecuzione). Dato che questo è un problema abbastanza comune con una propensione -alle corse critiche, dovreste usare del_timer_sync() -(``include/linux/timer.h``) per gestire questo caso. Questa ritorna il -numero di volte che il temporizzatore è stato interrotto prima che -fosse in grado di fermarlo senza che si riavviasse. +alle corse critiche, dovreste usare timer_delete_sync() +(``include/linux/timer.h``) per gestire questo caso. Velocità della sincronizzazione =============================== @@ -1374,7 +1372,7 @@ contesto, o trattenendo un qualsiasi *lock*. - kfree() -- add_timer() e del_timer() +- add_timer() e timer_delete() Riferimento per l'API dei Mutex =============================== diff --git a/Documentation/translations/zh_CN/core-api/local_ops.rst b/Documentation/translations/zh_CN/core-api/local_ops.rst index 41e4525038e8..eb5423f60f17 100644 --- a/Documentation/translations/zh_CN/core-api/local_ops.rst +++ b/Documentation/translations/zh_CN/core-api/local_ops.rst @@ -185,7 +185,7 @@ UP之间没有不同的行为,在你的架构的 ``local.h`` 中包括 ``asm-g static void __exit test_exit(void) { - del_timer_sync(&test_timer); + timer_shutdown_sync(&test_timer); } module_init(test_init); |