[PATCH 3/4] typesafe: kthread_create and kthread_run - Kernel

This is a discussion on [PATCH 3/4] typesafe: kthread_create and kthread_run - Kernel ; (Assumes patch to add printf attr to kthread_create is applied, but fixup trivial) Straight-forward conversion to allow typesafe callbacks. Signed-off-by: Rusty Russell --- include/linux/kthread.h | 28 +++++++++++++++++++++++++--- kernel/kthread.c | 29 +++++------------------------ 2 files changed, 30 insertions(+), 27 deletions(-) diff -r ...

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Thread: [PATCH 3/4] typesafe: kthread_create and kthread_run

  1. [PATCH 3/4] typesafe: kthread_create and kthread_run

    (Assumes patch to add printf attr to kthread_create is applied, but fixup trivial)

    Straight-forward conversion to allow typesafe callbacks.

    Signed-off-by: Rusty Russell
    ---
    include/linux/kthread.h | 28 +++++++++++++++++++++++++---
    kernel/kthread.c | 29 +++++------------------------
    2 files changed, 30 insertions(+), 27 deletions(-)

    diff -r f5a7f7f9683c include/linux/kthread.h
    --- a/include/linux/kthread.h Mon Apr 07 18:36:20 2008 +1000
    +++ b/include/linux/kthread.h Mon Apr 07 19:12:04 2008 +1000
    @@ -4,9 +4,31 @@
    #include
    #include

    -struct task_struct *kthread_create(int (*threadfn)(void *data),
    - void *data,
    - const char namefmt[], ...)
    +/**
    + * kthread_create - create a kthread.
    + * @threadfn: the function to run until signal_pending(current).
    + * @data: data ptr for @threadfn.
    + * @namefmt: printf-style name for the thread.
    + *
    + * Description: This helper function creates and names a kernel
    + * thread. The thread will be stopped: use wake_up_process() to start
    + * it. See also kthread_run(), kthread_create_on_cpu().
    + *
    + * When woken, the thread will run @threadfn() with @data as its
    + * argument. @threadfn() can either call do_exit() directly if it is a
    + * standalone thread for which noone will call kthread_stop(), or
    + * return when 'kthread_should_stop()' is true (which means
    + * kthread_stop() has been called). The return value should be zero
    + * or a negative error number; it will be passed to kthread_stop().
    + *
    + * Returns a task_struct or ERR_PTR(-ENOMEM).
    + */
    +#define kthread_create(threadfn, data, namefmt...) \
    + __kthread_create(typesafe_cb(int,(threadfn),(data) ), (data), namefmt)
    +
    +struct task_struct *__kthread_create(int (*threadfn)(void *data),
    + void *data,
    + const char namefmt[], ...)
    __attribute__((format(printf, 3, 4)));

    /**
    diff -r f5a7f7f9683c kernel/kthread.c
    --- a/kernel/kthread.c Mon Apr 07 18:36:20 2008 +1000
    +++ b/kernel/kthread.c Mon Apr 07 19:12:04 2008 +1000
    @@ -112,29 +112,10 @@ static void create_kthread(struct kthrea
    complete(&create->done);
    }

    -/**
    - * kthread_create - create a kthread.
    - * @threadfn: the function to run until signal_pending(current).
    - * @data: data ptr for @threadfn.
    - * @namefmt: printf-style name for the thread.
    - *
    - * Description: This helper function creates and names a kernel
    - * thread. The thread will be stopped: use wake_up_process() to start
    - * it. See also kthread_run(), kthread_create_on_cpu().
    - *
    - * When woken, the thread will run @threadfn() with @data as its
    - * argument. @threadfn() can either call do_exit() directly if it is a
    - * standalone thread for which noone will call kthread_stop(), or
    - * return when 'kthread_should_stop()' is true (which means
    - * kthread_stop() has been called). The return value should be zero
    - * or a negative error number; it will be passed to kthread_stop().
    - *
    - * Returns a task_struct or ERR_PTR(-ENOMEM).
    - */
    -struct task_struct *kthread_create(int (*threadfn)(void *data),
    - void *data,
    - const char namefmt[],
    - ...)
    +struct task_struct *__kthread_create(int (*threadfn)(void *data),
    + void *data,
    + const char namefmt[],
    + ...)
    {
    struct kthread_create_info create;

    @@ -159,7 +140,7 @@ struct task_struct *kthread_create(int (
    }
    return create.result;
    }
    -EXPORT_SYMBOL(kthread_create);
    +EXPORT_SYMBOL(__kthread_create);

    /**
    * kthread_bind - bind a just-created kthread to a cpu.
    --
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  2. [PATCH 4/4] typesafe: TIMER_INITIALIZER and setup_timer

    This patch lets timer callback functions have their natural type
    (ie. exactly match the data pointer type); it allows the old "unsigned
    long data" type as well.

    Downside: if you use the old "unsigned long" callback type, you won't
    get a warning if your data is not an unsigned long, due to the cast.

    Signed-off-by: Rusty Russell
    ---
    include/linux/timer.h | 32 +++++++++++++++++++++++---------
    1 file changed, 23 insertions(+), 9 deletions(-)

    diff -r 138795de70da include/linux/timer.h
    --- a/include/linux/timer.h Thu May 01 21:03:51 2008 +1000
    +++ b/include/linux/timer.h Thu May 01 21:05:13 2008 +1000
    @@ -25,12 +25,22 @@ struct timer_list {

    extern struct tvec_base boot_tvec_bases;

    -#define TIMER_INITIALIZER(_function, _expires, _data) { \
    - .entry = { .prev = TIMER_ENTRY_STATIC }, \
    - .function = (_function), \
    - .expires = (_expires), \
    - .data = (_data), \
    - .base = &boot_tvec_bases, \
    +/*
    + * For historic reasons the timer function takes an unsigned long, so
    + * we use this variant of typesafe_cb. data is converted to an unsigned long
    + * if it is another integer type, by adding 0UL.
    + */
    +#define typesafe_timerfn(fn, data) \
    + __typesafe_cb(void (*)(unsigned long), (fn), \
    + void (*)(const typeof((data)+0UL)), \
    + void (*)(typeof((data)+0UL)))
    +
    +#define TIMER_INITIALIZER(_function, _expires, _data) { \
    + .entry = { .prev = TIMER_ENTRY_STATIC }, \
    + .function = typesafe_timerfn((_function), (_data)), \
    + .expires = (_expires), \
    + .data = (unsigned long)(_data), \
    + .base = &boot_tvec_bases, \
    }

    #define DEFINE_TIMER(_name, _function, _expires, _data) \
    @@ -51,9 +61,13 @@ static inline void init_timer_on_stack(s
    }
    #endif

    -static inline void setup_timer(struct timer_list * timer,
    - void (*function)(unsigned long),
    - unsigned long data)
    +#define setup_timer(timer, function, data) \
    + __setup_timer((timer), typesafe_timerfn((function), (data)), \
    + (unsigned long)(data))
    +
    +static inline void __setup_timer(struct timer_list *timer,
    + void (*function)(unsigned long),
    + unsigned long data)
    {
    timer->function = function;
    timer->data = data;
    --
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