[PATCH 00/21] hrtimers: Switch to new hrtimer interface functions (1/5)

[Nam Cao <namcao@linutronix.de>]

This is the first part of a 5-part series (split for convenience). All 5
parts are:

Part 1: https://lore.kernel.org/lkml/cover.1729864615.git.namcao@linutronix.de
Part 2: https://lore.kernel.org/lkml/cover.1729864823.git.namcao@linutronix.de
Part 3: https://lore.kernel.org/lkml/cover.1729865232.git.namcao@linutronix.de
Part 4: https://lore.kernel.org/lkml/cover.1729865485.git.namcao@linutronix.de
Part 5: https://lore.kernel.org/lkml/cover.1729865740.git.namcao@linutronix.de

To use hrtimer, hrtimer_init() (or one of its variant) must be called, and
also the timer's callfack function must be setup separately.

That can cause misuse of hrtimer. For example, because:
  - The callback function is not setup
  - The callback function is setup while it is not safe to do so

To prevent misuse of hrtimer, this series:
  - Introduce new functions hrtimer_setup*(). These new functions are
    similar to hrtimer_init*(), except that they also sanity-check and
    initialize the callback function.
  - Introduce hrtimer_update_function() which checks that it is safe to
    change the callback function. The 'function' field of hrtimer is then
    made private.
  - Convert all users to use the new functions.
  - Some minor cleanups on the way.

Most conversion patches were created using Coccinelle with the sematic
patch below; except for tricky cases that Coccinelle cannot handle, or for
some cases where a Coccinelle's bug regarding 100 column limit is
triggered. Any patches not mentioning Coccinelle were done manually.

virtual patch
@@ expression timer, clock, mode, func; @@
- hrtimer_init(timer, clock, mode);
  ...
- timer->function = func;
+ hrtimer_setup(timer, func, clock, mode);

@@ expression timer, clock, mode, func; @@
- hrtimer_init(&timer, clock, mode);
  ...
- timer.function = func;
+ hrtimer_setup(&timer, func, clock, mode);

@@ expression timer, clock, mode, func; @@
- hrtimer_init_on_stack(&timer, clock, mode);
  ...
- timer.function = func;
+ hrtimer_setup_on_stack(&timer, func, clock, mode);

@@ expression timer, clock, mode; @@
- hrtimer_init_sleeper_on_stack(timer, clock, mode);
+ hrtimer_setup_sleeper_on_stack(timer, clock, mode);

Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: x86@kernel.org
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <jstultz@google.com>

Nam Cao (21):
  hrtimers: Add missing hrtimer_init event trace points
  hrtimers: Remove unused hrtimer_init_sleeper()
  drm/i915/request: Remove unnecessary abuse of hrtimer::function
  KVM: x86/xen: Initialize hrtimer in kvm_xen_init_vcpu()
  can: bcm: Don't initialized an unused hrtimer
  wifi: rt2x00: Remove redundant hrtimer_init()
  io_uring: Remove redundant hrtimer's callback function setup
  hrtimers: Introduce hrtimer_setup() to replace hrtimer_init()
  hrtimers: Introduce hrtimer_setup_on_stack()
  hrtimers: Introduce hrtimer_setup_sleeper_on_stack()
  hrtimers: Introduce hrtimer_update_function()
  fs/aio: Switch to use hrtimer_setup_sleeper_on_stack()
  futex: Switch to use hrtimer_setup_sleeper_on_stack()
  net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack()
  timers: Switch to use hrtimer_setup_sleeper_on_stack()
  wait: Switch to use hrtimer_setup_sleeper_on_stack()
  hrtimers: Delete hrtimer_init_sleeper_on_stack()
  sched/idle: Switch to use hrtimer_setup_on_stack()
  io_uring: Switch to use hrtimer_setup_on_stack()
  alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack()
  hrtimers: Delete hrtimer_init_on_stack()

 arch/x86/kvm/xen.c                            |   4 +-
 drivers/gpu/drm/i915/i915_request.c           |  17 +--
 .../net/wireless/ralink/rt2x00/rt2x00usb.c    |   2 -
 fs/aio.c                                      |   2 +-
 include/linux/hrtimer.h                       |  51 ++++----
 include/linux/wait.h                          |   4 +-
 io_uring/io_uring.c                           |   7 +-
 io_uring/timeout.c                            |   1 -
 kernel/futex/core.c                           |   6 +-
 kernel/sched/idle.c                           |   4 +-
 kernel/time/alarmtimer.c                      |   9 +-
 kernel/time/hrtimer.c                         | 110 +++++++++++++-----
 kernel/time/sleep_timeout.c                   |   2 +-
 net/can/bcm.c                                 |  19 ++-
 net/core/pktgen.c                             |   2 +-
 15 files changed, 143 insertions(+), 97 deletions(-)

-- 
2.39.5