treewide: Switch/rename to timer_delete[_sync]()

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with c

treewide: Switch/rename to timer_delete[_sync]()

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with coccinelle plus manual fixups where necessary.

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

timers: Fix kernel-doc format and add Return values

Fix kernel-doc format and warnings:

timer.h:26: warning: Cannot understand * @TIMER_DEFERRABLE: A deferrable timer will work normally when the

timers: Fix kernel-doc format and add Return values

Fix kernel-doc format and warnings:

timer.h:26: warning: Cannot understand * @TIMER_DEFERRABLE: A deferrable timer will work normally when the on line 26 - I thought it was a doc line
timer.h:146: warning: No description found for return value of 'timer_pending'
timer.h:180: warning: No description found for return value of 'del_timer_sync'
timer.h:193: warning: No description found for return value of 'del_timer'

Signed-off-by: Randy Dunlap <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

timers: Always queue timers on the local CPU

The timer pull model is in place so we can remove the heuristics which try
to guess the best target CPU at enqueue/modification time.

All non pinned tim

timers: Always queue timers on the local CPU

The timer pull model is in place so we can remove the heuristics which try
to guess the best target CPU at enqueue/modification time.

All non pinned timers are queued on the local CPU in the separate storage
and eventually pulled at expiry time to a remote CPU.

Originally-by: Richard Cochran (linutronix GmbH) <[email protected]>
Signed-off-by: Anna-Maria Behnsen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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timers: Introduce add_timer() variants which modify timer flags

A timer might be used as a pinned timer (using add_timer_on()) and later on
as non-pinned timer using add_timer(). When the "NOHZ time

timers: Introduce add_timer() variants which modify timer flags

A timer might be used as a pinned timer (using add_timer_on()) and later on
as non-pinned timer using add_timer(). When the "NOHZ timer pull at expiry
model" is in place, the TIMER_PINNED flag is required to be used whenever a
timer needs to expire on a dedicated CPU. Otherwise the flag must not be
set if expiration on a dedicated CPU is not required.

add_timer_on()'s behavior will be changed during the preparation patches
for the "NOHZ timer pull at expiry model" to unconditionally set the
TIMER_PINNED flag. To be able to clear/ set the flag when queueing a
timer, two variants of add_timer() are introduced.

This is a preparatory step and has no functional change.

Signed-off-by: Anna-Maria Behnsen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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timers: Split out timer_types.h

Cutting down on sched.h dependencies: this is going to be used in
workqueue_types.h in the next patch, so we can kill the sched.h
dependency on workqueue.h.

Signed-o

timers: Split out timer_types.h

Cutting down on sched.h dependencies: this is going to be used in
workqueue_types.h in the next patch, so we can kill the sched.h
dependency on workqueue.h.

Signed-off-by: Kent Overstreet <[email protected]>

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extract and use FILE_LINE macro

Extract nifty FILE_LINE useful for printk style debugging:

printk("%s\n", FILE_LINE);

It should not be used en mass probably because __FILE__ string literals
can b

extract and use FILE_LINE macro

Extract nifty FILE_LINE useful for printk style debugging:

printk("%s\n", FILE_LINE);

It should not be used en mass probably because __FILE__ string literals
can be merged while FILE_LINE's won't. But for debugging it is what
the doctor ordered.

Don't add leading and trailing underscores, they're painful to type.
Trust me, I've tried both versions.

Link: https://lkml.kernel.org/r/ebf12ac4-5a61-4b12-b8b0-1253eb371332@p183
Signed-off-by: Alexey Dobriyan <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Takashi Iwai <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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timers: Provide timer_shutdown[_sync]()

Tearing down timers which have circular dependencies to other
functionality, e.g. workqueues, where the timer can schedule work and work
can arm timers, is no

timers: Provide timer_shutdown[_sync]()

Tearing down timers which have circular dependencies to other
functionality, e.g. workqueues, where the timer can schedule work and work
can arm timers, is not trivial.

In those cases it is desired to shutdown the timer in a way which prevents
rearming of the timer. The mechanism to do so is to set timer->function to
NULL and use this as an indicator for the timer arming functions to ignore
the (re)arm request.

Expose new interfaces for this: timer_shutdown_sync() and timer_shutdown().

timer_shutdown_sync() has the same functionality as timer_delete_sync()
plus the NULL-ification of the timer function.

timer_shutdown() has the same functionality as timer_delete() plus the
NULL-ification of the timer function.

In both cases the rearming of the timer is prevented by silently discarding
rearm attempts due to timer->function being NULL.

Co-developed-by: Steven Rostedt <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Anna-Maria Behnsen <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Link: https://lore.kernel.org/all/[email protected]
Link: https://lore.kernel.org/r/[email protected]

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timers: Rename del_timer() to timer_delete()

The timer related functions do not have a strict timer_ prefixed namespace
which is really annoying.

Rename del_timer() to timer_delete() and provide de

timers: Rename del_timer() to timer_delete()

The timer related functions do not have a strict timer_ prefixed namespace
which is really annoying.

Rename del_timer() to timer_delete() and provide del_timer()
as a wrapper. Document that del_timer() is not for new code.

Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Steven Rostedt (Google) <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Anna-Maria Behnsen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

timers: Rename del_timer_sync() to timer_delete_sync()

The timer related functions do not have a strict timer_ prefixed namespace
which is really annoying.

Rename del_timer_sync() to timer_delete_s

timers: Rename del_timer_sync() to timer_delete_sync()

The timer related functions do not have a strict timer_ prefixed namespace
which is really annoying.

Rename del_timer_sync() to timer_delete_sync() and provide del_timer_sync()
as a wrapper. Document that del_timer_sync() is not for new code.

Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Steven Rostedt (Google) <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Anna-Maria Behnsen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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timers: Use del_timer_sync() even on UP

del_timer_sync() is assumed to be pointless on uniprocessor systems and can
be mapped to del_timer() because in theory del_timer() can never be invoked
while

timers: Use del_timer_sync() even on UP

del_timer_sync() is assumed to be pointless on uniprocessor systems and can
be mapped to del_timer() because in theory del_timer() can never be invoked
while the timer callback function is executed.

This is not entirely true because del_timer() can be invoked from interrupt
context and therefore hit in the middle of a running timer callback.

Contrary to that del_timer_sync() is not allowed to be invoked from
interrupt context unless the affected timer is marked with TIMER_IRQSAFE.
del_timer_sync() has proper checks in place to detect such a situation.

Give up on the UP optimization and make del_timer_sync() unconditionally
available.

Co-developed-by: Steven Rostedt <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Anna-Maria Behnsen <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Link: https://lore.kernel.org/all/[email protected]
Link: https://lore.kernel.org/r/[email protected]

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timers: Get rid of del_singleshot_timer_sync()

del_singleshot_timer_sync() used to be an optimization for deleting timers
which are not rearmed from the timer callback function.

This optimization t

timers: Get rid of del_singleshot_timer_sync()

del_singleshot_timer_sync() used to be an optimization for deleting timers
which are not rearmed from the timer callback function.

This optimization turned out to be broken and got mapped to
del_timer_sync() about 17 years ago.

Get rid of the undocumented indirection and use del_timer_sync() directly.

No functional change.

Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Anna-Maria Behnsen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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timers: Move timer sysctl into the timer code

This is part of the effort to reduce kernel/sysctl.c to only contain the
core logic.

Signed-off-by: tangmeng <[email protected]>
Signed-off-by: Th

timers: Move timer sysctl into the timer code

This is part of the effort to reduce kernel/sysctl.c to only contain the
core logic.

Signed-off-by: tangmeng <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

timer: Revert "timer: Add timer_curr_running()"

This reverts commit dcd42591ebb8a25895b551a5297ea9c24414ba54.
The only user was RCU/nocb.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc

timer: Revert "timer: Add timer_curr_running()"

This reverts commit dcd42591ebb8a25895b551a5297ea9c24414ba54.
The only user was RCU/nocb.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

timer: Add timer_curr_running()

This commit adds a timer_curr_running() function that verifies that the
current code is running in the context of the specified timer's handler.

Cc: Josh Triplett <j

timer: Add timer_curr_running()

This commit adds a timer_curr_running() function that verifies that the
current code is running in the context of the specified timer's handler.

Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Tested-by: Boqun Feng <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

timers: Make run_local_timers() static

No users outside of the timer code. Move the caller below this function to
avoid a pointless forward declaration.

Signed-off-by: Thomas Gleixner <tglx@linutro

timers: Make run_local_timers() static

No users outside of the timer code. Move the caller below this function to
avoid a pointless forward declaration.

Signed-off-by: Thomas Gleixner <[email protected]>

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timers: Mask invalid flags in do_init_timer()

do_init_timer() accepts any combination of timer flags handed in by the
caller without a sanity check, but only TIMER_DEFFERABLE, TIMER_PINNED and
TIMER

timers: Mask invalid flags in do_init_timer()

do_init_timer() accepts any combination of timer flags handed in by the
caller without a sanity check, but only TIMER_DEFFERABLE, TIMER_PINNED and
TIMER_IRQSAFE are valid.

If the supplied flags have other bits set, this could result in
malfunction. If bits are set in TIMER_CPUMASK the first timer usage could
deference a cpu base which is outside the range of possible CPUs. If
TIMER_MIGRATION is set, then the switch_timer_base() will live lock.

Prevent that with a sanity check which warns when invalid flags are
supplied and masks them out.

[ tglx: Made it WARN_ON_ONCE() and added context to the changelog ]

Signed-off-by: Qianli Zhao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/9d79a8aa4eb56713af7379f99f062dedabcde140.1597326756.git.zhaoqianli@xiaomi.com

show more ...

sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from u

sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Andrey Ignatov <[email protected]>
Signed-off-by: Al Viro <[email protected]>

show more ...

timer: Use hlist_unhashed_lockless() in timer_pending()

The timer_pending() function is mostly used in lockless contexts, so
Without proper annotations, KCSAN might detect a data-race [1].

Using hl

timer: Use hlist_unhashed_lockless() in timer_pending()

The timer_pending() function is mostly used in lockless contexts, so
Without proper annotations, KCSAN might detect a data-race [1].

Using hlist_unhashed_lockless() instead of hand-coding it seems
appropriate (as suggested by Paul E. McKenney).

[1]

BUG: KCSAN: data-race in del_timer / detach_if_pending

write to 0xffff88808697d870 of 8 bytes by task 10 on cpu 0:
__hlist_del include/linux/list.h:764 [inline]
detach_timer kernel/time/timer.c:815 [inline]
detach_if_pending+0xcd/0x2d0 kernel/time/timer.c:832
try_to_del_timer_sync+0x60/0xb0 kernel/time/timer.c:1226
del_timer_sync+0x6b/0xa0 kernel/time/timer.c:1365
schedule_timeout+0x2d2/0x6e0 kernel/time/timer.c:1896
rcu_gp_fqs_loop+0x37c/0x580 kernel/rcu/tree.c:1639
rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1799
kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff88808697d870 of 8 bytes by task 12060 on cpu 1:
del_timer+0x3b/0xb0 kernel/time/timer.c:1198
sk_stop_timer+0x25/0x60 net/core/sock.c:2845
inet_csk_clear_xmit_timers+0x69/0xa0 net/ipv4/inet_connection_sock.c:523
tcp_clear_xmit_timers include/net/tcp.h:606 [inline]
tcp_v4_destroy_sock+0xa3/0x3f0 net/ipv4/tcp_ipv4.c:2096
inet_csk_destroy_sock+0xf4/0x250 net/ipv4/inet_connection_sock.c:836
tcp_close+0x6f3/0x970 net/ipv4/tcp.c:2497
inet_release+0x86/0x100 net/ipv4/af_inet.c:427
__sock_release+0x85/0x160 net/socket.c:590
sock_close+0x24/0x30 net/socket.c:1268
__fput+0x1e1/0x520 fs/file_table.c:280
____fput+0x1f/0x30 fs/file_table.c:313
task_work_run+0xf6/0x130 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:163

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12060 Comm: syz-executor.5 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine,

Signed-off-by: Eric Dumazet <[email protected]>
Cc: Thomas Gleixner <[email protected]>
[ paulmck: Pulled in Eric's later amendments. ]
Signed-off-by: Paul E. McKenney <[email protected]>

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timers: Prepare support for PREEMPT_RT

When PREEMPT_RT is enabled, the soft interrupt thread can be preempted. If
the soft interrupt thread is preempted in the middle of a timer callback,
then call

timers: Prepare support for PREEMPT_RT

When PREEMPT_RT is enabled, the soft interrupt thread can be preempted. If
the soft interrupt thread is preempted in the middle of a timer callback,
then calling del_timer_sync() can lead to two issues:

- If the caller is on a remote CPU then it has to spin wait for the timer
handler to complete. This can result in unbound priority inversion.

- If the caller originates from the task which preempted the timer
handler on the same CPU, then spin waiting for the timer handler to
complete is never going to end.

To avoid these issues, add a new lock to the timer base which is held
around the execution of the timer callbacks. If del_timer_sync() detects
that the timer callback is currently running, it blocks on the expiry
lock. When the callback is finished, the expiry lock is dropped by the
softirq thread which wakes up the waiter and the system makes progress.

This addresses both the priority inversion and the life lock issues.

This mechanism is not used for timers which are marked IRQSAFE as for those
preemption is disabled accross the callback and therefore this situation
cannot happen. The callbacks for such timers need to be individually
audited for RT compliance.

The same issue can happen in virtual machines when the vCPU which runs a
timer callback is scheduled out. If a second vCPU of the same guest calls
del_timer_sync() it will spin wait for the other vCPU to be scheduled back
in. The expiry lock mechanism would avoid that. It'd be trivial to enable
this when paravirt spinlocks are enabled in a guest, but it's not clear
whether this is an actual problem in the wild, so for now it's an RT only
mechanism.

As the softirq thread can be preempted with PREEMPT_RT=y, the SMP variant
of del_timer_sync() needs to be used on UP as well.

[ tglx: Refactored it for mainline ]

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

timer: Document TIMER_PINNED

The flag hints the user that the pinned timers will always be run on a
static CPU (because that should be what "pinned" means...) but that's
not the truth, at least with

timer: Document TIMER_PINNED

The flag hints the user that the pinned timers will always be run on a
static CPU (because that should be what "pinned" means...) but that's
not the truth, at least with the current implementation.

For example, currently if a pinned timer is set up but later mod_timer()
upon the pinned timer is invoked, mod_timer() will still try to queue the
timer on the current processor and migrate the timer if necessary.

Document it a bit with the definition of TIMER_PINNED so that all future
users will use it correctly.

Signed-off-by: Peter Xu <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Luiz Capitulino <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

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timers: Remove stale struct tvec_base forward declaration

struct tvec_base is a leftover of the original timer wheel implementation
and not longer used. Remove the forward declaration.

Signed-off-b

timers: Remove stale struct tvec_base forward declaration

struct tvec_base is a leftover of the original timer wheel implementation
and not longer used. Remove the forward declaration.

Signed-off-by: Liu Changcheng <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/20180412075701.GA38952@sofia

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timers: Reinitialize per cpu bases on hotplug

The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trou

timers: Reinitialize per cpu bases on hotplug

The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.

Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.

Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.

Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Sebastian Siewior <[email protected]>
Cc: Anna-Maria Gleixner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos

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treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts

With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. C

treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts

With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:

perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
$(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)

perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
$(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)

The now unused macros are also dropped from include/linux/timer.h.

Signed-off-by: Kees Cook <[email protected]>

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timer: Remove redundant __setup_timer*() macros

With __init_timer*() now matching __setup_timer*(), remove the redundant
internal interface, clean up the resulting definitions and add more
documenta

timer: Remove redundant __setup_timer*() macros

With __init_timer*() now matching __setup_timer*(), remove the redundant
internal interface, clean up the resulting definitions and add more
documentation.

Cc: Thomas Gleixner <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

show more ...

timer: Pass function down to initialization routines

In preparation for removing more macros, pass the function down to the
initialization routines instead of doing it in macros.

Cc: Thomas Gleixne

timer: Pass function down to initialization routines

In preparation for removing more macros, pass the function down to the
initialization routines instead of doing it in macros.

Cc: Thomas Gleixner <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Stephen Boyd <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

show more ...