Commit 52782c92 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

kthread: save thread function 



It's handy to keep the kthread_fn just as a unique cookie to identify
classes of kthreads.  E.g. if you can verify that a given task is
running your thread_fn, then you may know what sort of type kthread_data
points to.

We'll use this in nfsd to pass some information into the vfs.  Note it
will need kthread_data() exported too.

Original-patch-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 31fb4bf5

include/linux/kthread.h

+1 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ bool kthread_should_stop(void); 
bool kthread_should_park(void);

bool __kthread_should_park(struct task_struct *k);

bool kthread_freezable_should_stop(bool *was_frozen);

void *kthread_func(struct task_struct *k);

void *kthread_data(struct task_struct *k);

void *kthread_probe_data(struct task_struct *k);

int kthread_park(struct task_struct *k);

kernel/kthread.c

+17 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ struct kthread_create_info 
struct kthread {

	unsigned long flags;

	unsigned int cpu;

	int (*threadfn)(void *);

	void *data;

	struct completion parked;

	struct completion exited;
@@ -152,6 +153,20 @@ bool kthread_freezable_should_stop(bool *was_frozen) 
}

EXPORT_SYMBOL_GPL(kthread_freezable_should_stop);



/**

 * kthread_func - return the function specified on kthread creation

 * @task: kthread task in question

 *

 * Returns NULL if the task is not a kthread.

 */

void *kthread_func(struct task_struct *task)

{

	if (task->flags & PF_KTHREAD)

		return to_kthread(task)->threadfn;

	return NULL;

}

EXPORT_SYMBOL_GPL(kthread_func);



/**

 * kthread_data - return data value specified on kthread creation

 * @task: kthread task in question
@@ -164,6 +179,7 @@ void *kthread_data(struct task_struct *task) 
{

	return to_kthread(task)->data;

}

EXPORT_SYMBOL_GPL(kthread_data);



/**

 * kthread_probe_data - speculative version of kthread_data()
@@ -244,6 +260,7 @@ static int kthread(void *_create) 
		do_exit(-ENOMEM);

	}



	self->threadfn = threadfn;

	self->data = data;

	init_completion(&self->exited);

	init_completion(&self->parked);

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