From: J. Bruce Fields bfields@redhat.com
[ Upstream commit 52782c92ac85c4e393eb4a903a62e6c24afa633f ]
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: Tejun Heo tj@kernel.org Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/kthread.h | 1 + kernel/kthread.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+)
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 0f9da966934e2..59bbc63ff8637 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -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); diff --git a/kernel/kthread.c b/kernel/kthread.c index b262f47046ca4..543dff6b576c7 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -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() @@ -237,6 +253,7 @@ static int kthread(void *_create) do_exit(-ENOMEM); }
+ self->threadfn = threadfn; self->data = data; init_completion(&self->exited); init_completion(&self->parked);