From b9eaf18722221ef8b2bd6a67240ebe668622152a Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Mon, 16 Oct 2017 13:15:39 -0700
Subject: treewide: init_timer() -> setup_timer()

This mechanically converts all remaining cases of ancient open-coded timer
setup with the old setup_timer() API, which is the first step in timer
conversions. This has no behavioral changes, since it ultimately just
changes the order of assignment to fields of struct timer_list when
finding variations of:

    init_timer(&t);
    f.function = timer_callback;
    t.data = timer_callback_arg;

to be converted into:

    setup_timer(&t, timer_callback, timer_callback_arg);

The conversion is done with the following Coccinelle script, which
is an improved version of scripts/cocci/api/setup_timer.cocci, in the
following ways:
 - assignments-before-init_timer() cases
 - limit the .data case removal to the specific struct timer_list instance
 - handling calls by dereference (timer->field vs timer.field)

spatch --very-quiet --all-includes --include-headers \
	-I ./arch/x86/include -I ./arch/x86/include/generated \
	-I ./include -I ./arch/x86/include/uapi \
	-I ./arch/x86/include/generated/uapi -I ./include/uapi \
	-I ./include/generated/uapi --include ./include/linux/kconfig.h \
	--dir . \
	--cocci-file ~/src/data/setup_timer.cocci

@fix_address_of@
expression e;
@@

 init_timer(
-&(e)
+&e
 , ...)

// Match the common cases first to avoid Coccinelle parsing loops with
// "... when" clauses.

@match_immediate_function_data_after_init_timer@
expression e, func, da;
@@

-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );
(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)

@match_immediate_function_data_before_init_timer@
expression e, func, da;
@@

(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)
-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );

@match_function_and_data_after_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@

-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );
 ... when != func = e2
     when != da = e3
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)

@match_function_and_data_before_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)
... when != func = e2
    when != da = e3
-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );

@r1 exists@
expression t;
identifier f;
position p;
@@

f(...) { ... when any
  init_timer@p(\(&t\|t\))
  ... when any
}

@r2 exists@
expression r1.t;
identifier g != r1.f;
expression e8;
@@

g(...) { ... when any
  \(t.data\|t->data\) = e8
  ... when any
}

// It is dangerous to use setup_timer if data field is initialized
// in another function.
@script:python depends on r2@
p << r1.p;
@@

cocci.include_match(False)

@r3@
expression r1.t, func, e7;
position r1.p;
@@

(
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
... when != func = e7
-t.function = func;
|
-t.function = func;
... when != func = e7
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
|
-init_timer@p(t);
+setup_timer(t, func, 0UL);
... when != func = e7
-t->function = func;
|
-t->function = func;
... when != func = e7
-init_timer@p(t);
+setup_timer(t, func, 0UL);
)

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 kernel/time/clocksource.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'kernel/time')

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 03918a19cf2d..5b51d5ba2a85 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -290,8 +290,7 @@ static inline void clocksource_start_watchdog(void)
 {
 	if (watchdog_running || !watchdog || list_empty(&watchdog_list))
 		return;
-	init_timer(&watchdog_timer);
-	watchdog_timer.function = clocksource_watchdog;
+	setup_timer(&watchdog_timer, clocksource_watchdog, 0UL);
 	watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
 	add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
 	watchdog_running = 1;
-- 
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