With a little macro ugliness, we can make kthread_create() and
kthread_run() typesafe: avoid the casts to and from void *. To do
this we use a temporary function pointer which takes the type of the
data as a callback: if the function doesn't match, we get:
warning: initialization from incompatible pointer type
It's actually slightly over-strict, since a void * would be compatible
with any function type, but there's only one such case in the kernel
anyway.
Signed-off-by: Rusty Russell <[EMAIL PROTECTED]>
---
include/linux/kthread.h | 30 +++++++++++++++++++++++++++---
kernel/kthread.c | 29 +++++------------------------
2 files changed, 32 insertions(+), 27 deletions(-)
diff -r 110aa94129d0 include/linux/kthread.h
--- a/include/linux/kthread.h Fri Jan 18 10:32:31 2008 +1100
+++ b/include/linux/kthread.h Fri Jan 18 11:31:49 2008 +1100
@@ -4,9 +4,33 @@
#include <linux/err.h>
#include <linux/sched.h>
-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...) ({ \
+ int (*_threadfn)(typeof(data)) = (threadfn); \
+ __kthread_create((void *)_threadfn, (data), namefmt); \
+})
+
+struct task_struct *__kthread_create(int (*threadfn)(void *data),
+ void *data,
+ const char namefmt[], ...);
/**
* kthread_run - create and wake a thread.
diff -r 110aa94129d0 kernel/kthread.c
--- a/kernel/kthread.c Fri Jan 18 10:32:31 2008 +1100
+++ b/kernel/kthread.c Fri Jan 18 11:31:49 2008 +1100
@@ -102,29 +102,10 @@ 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;
@@ -149,7 +130,7 @@ 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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