linux-toradex.git/include/linux/hrtimer.h, branch v6.16-rc6

hrtimer: Add missing ACCESS_PRIVATE() for hrtimer::function

2025-04-09T19:00:42+00:00

The "function" field of struct hrtimer has been changed to private, but
two instances have not been converted to use ACCESS_PRIVATE().

Convert them to use ACCESS_PRIVATE().

Fixes: 04257da0c99c ("hrtimers: Make callback function pointer private")
Reported-by: kernel test robot 
Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20250408103854.1851093-1-namcao@linutronix.de
Closes: https://lore.kernel.org/oe-kbuild-all/202504071931.vOVl13tt-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202504072155.5UAZjYGU-lkp@intel.com/

hrtimers: Delete hrtimer_init()

2025-04-05T08:30:17+00:00

hrtimer_init() is now unused. Delete it.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/all/003722f60c7a2a4f8d4ed24fb741aa313b7e5136.1738746927.git.namcao@linutronix.de

Merge tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-03-25T17:54:15+00:00

Pull timer cleanups from Thomas Gleixner:
 "A treewide hrtimer timer cleanup

  hrtimers are initialized with hrtimer_init() and a subsequent store to
  the callback pointer. This turned out to be suboptimal for the
  upcoming Rust integration and is obviously a silly implementation to
  begin with.

  This cleanup replaces the hrtimer_init(T); T->function = cb; sequence
  with hrtimer_setup(T, cb);

  The conversion was done with Coccinelle and a few manual fixups.

  Once the conversion has completely landed in mainline, hrtimer_init()
  will be removed and the hrtimer::function becomes a private member"

* tag 'timers-cleanups-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (100 commits)
  wifi: rt2x00: Switch to use hrtimer_update_function()
  io_uring: Use helper function hrtimer_update_function()
  serial: xilinx_uartps: Use helper function hrtimer_update_function()
  ASoC: fsl: imx-pcm-fiq: Switch to use hrtimer_setup()
  RDMA: Switch to use hrtimer_setup()
  virtio: mem: Switch to use hrtimer_setup()
  drm/vmwgfx: Switch to use hrtimer_setup()
  drm/xe/oa: Switch to use hrtimer_setup()
  drm/vkms: Switch to use hrtimer_setup()
  drm/msm: Switch to use hrtimer_setup()
  drm/i915/request: Switch to use hrtimer_setup()
  drm/i915/uncore: Switch to use hrtimer_setup()
  drm/i915/pmu: Switch to use hrtimer_setup()
  drm/i915/perf: Switch to use hrtimer_setup()
  drm/i915/gvt: Switch to use hrtimer_setup()
  drm/i915/huc: Switch to use hrtimer_setup()
  drm/amdgpu: Switch to use hrtimer_setup()
  stm class: heartbeat: Switch to use hrtimer_setup()
  i2c: Switch to use hrtimer_setup()
  iio: Switch to use hrtimer_setup()
  ...

can: Switch to use hrtimer_setup()

2025-02-18T09:35:45+00:00

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initialization of
hrtimer::function with the new setup mechanism.

Most of this patch is generated by Coccinelle. Except for the TX thrtimer
in bcm_tx_setup() because this timer is not used and the callback function
is never set. For this particular case, set the callback to
hrtimer_dummy_timeout()

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Marc Kleine-Budde 
Link: https://lore.kernel.org/all/a3a6be42c818722ad41758457408a32163bfd9a0.1738746872.git.namcao@linutronix.de

hrtimers: Make hrtimer_update_function() less expensive

2025-02-10T19:51:12+00:00

The sanity checks in hrtimer_update_function() are expensive for high
frequency usage like in the io/uring code due to locking.

Hide the sanity checks behind CONFIG_PROVE_LOCKING, which has a decent
chance to be enabled on a regular basis for testing.

Fixes: 8f02e3563bb5 ("hrtimers: Introduce hrtimer_update_function()")
Reported-by: Jens Axboe 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/87ikpllali.ffs@tglx

hrtimers: Handle CPU state correctly on hotplug

2025-01-16T12:06:14+00:00

Consider a scenario where a CPU transitions from CPUHP_ONLINE to halfway
through a CPU hotunplug down to CPUHP_HRTIMERS_PREPARE, and then back to
CPUHP_ONLINE:

Since hrtimers_prepare_cpu() does not run, cpu_base.hres_active remains set
to 1 throughout. However, during a CPU unplug operation, the tick and the
clockevents are shut down at CPUHP_AP_TICK_DYING. On return to the online
state, for instance CFS incorrectly assumes that the hrtick is already
active, and the chance of the clockevent device to transition to oneshot
mode is also lost forever for the CPU, unless it goes back to a lower state
than CPUHP_HRTIMERS_PREPARE once.

This round-trip reveals another issue; cpu_base.online is not set to 1
after the transition, which appears as a WARN_ON_ONCE in enqueue_hrtimer().

Aside of that, the bulk of the per CPU state is not reset either, which
means there are dangling pointers in the worst case.

Address this by adding a corresponding startup() callback, which resets the
stale per CPU state and sets the online flag.

[ tglx: Make the new callback unconditionally available, remove the online
  	modification in the prepare() callback and clear the remaining
  	state in the starting callback instead of the prepare callback ]

Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Signed-off-by: Koichiro Den 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20241220134421.3809834-1-koichiro.den@canonical.com

hrtimers: Delete hrtimer_init_on_stack()

2024-11-07T01:47:07+00:00

hrtimer_init_on_stack() is now unused. Delete it.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/510ce0d2944c4a382ea51e51d03dcfb73ba0f4f7.1730386209.git.namcao@linutronix.de

hrtimers: Delete hrtimer_init_sleeper_on_stack()

2024-11-07T01:47:06+00:00

hrtimer_init_sleeper_on_stack() is now unused. Delete it.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/52549846635c0b3a2abf82101f539efdabcd9778.1730386209.git.namcao@linutronix.de

hrtimers: Introduce hrtimer_update_function()

2024-11-07T01:47:05+00:00

Some users of hrtimer need to change the callback function after the
initial setup. They write to hrtimer::function directly.

That's not safe under all circumstances as the write is lockless and a
concurrent timer expiry might end up using the wrong function pointer.

Introduce hrtimer_update_function(), which also performs runtime checks
whether it is safe to modify the callback.

This allows to make hrtimer::function private once all users are converted.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/20a937b0ae09ad54b5b6d86eabead7c570f1b72e.1730386209.git.namcao@linutronix.de

hrtimers: Introduce hrtimer_setup_sleeper_on_stack()

2024-11-07T01:47:05+00:00

The hrtimer_init*() API is replaced by hrtimer_setup*() variants to
initialize the timer including the callback function at once.

hrtimer_init_sleeper_on_stack() does not need user to setup the callback
function separately, so a new variant would not be strictly necessary.

Nonetheless, to keep the naming convention consistent, introduce
hrtimer_setup_sleeper_on_stack(). hrtimer_init_on_stack() will be removed
once all users are converted.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/7b5e18e6dd0ace9eaa211201528cb9dc23752454.1730386209.git.namcao@linutronix.de