[PATCH 4/4] kthreads: allow cloning threads with different flags

[J. Bruce Fields]

From: "J. Bruce Fields" <bfie...@redhat.com>

This is so knfsd can add CLONE_THREAD.

Signed-off-by: J. Bruce Fields <bfie...@redhat.com>
---
 include/linux/kthread.h |  3 ++-
 kernel/kthread.c        | 11 +++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index a7ffdf96a3b2..7069feb6da65 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -10,11 +10,12 @@ struct kthread_group {
        spinlock_t create_lock;
        struct list_head create_list;
        struct task_struct *task;
+       unsigned long flags;
 };
 
 extern struct kthread_group kthreadd_default;
 
-struct kthread_group *kthread_start_group(char *);
+struct kthread_group *kthread_start_group(unsigned long, char *);
 void kthread_stop_group(struct kthread_group *);
 
 struct task_struct *kthread_group_create_on_node(struct kthread_group *,
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5232f6f597b5..57f6687ecec7 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -29,6 +29,7 @@ struct kthread_group kthreadd_default = {
        .name = "kthreadd",
        .create_lock = __SPIN_LOCK_UNLOCKED(kthreadd_default.create_lock),
        .create_list = LIST_HEAD_INIT(kthreadd_default.create_list),
+       .flags = CLONE_FS | CLONE_FILES | SIGCHLD,
 };
 
 void wake_kthreadd(struct kthread_group *kg)
@@ -36,7 +37,7 @@ void wake_kthreadd(struct kthread_group *kg)
        wake_up_process(kg->task);
 }
 
-struct kthread_group *kthread_start_group(char *name)
+struct kthread_group *kthread_start_group(unsigned long flags, char *name)
 {
        struct kthread_group *new;
        struct task_struct *task;
@@ -47,6 +48,7 @@ struct kthread_group *kthread_start_group(char *name)
        spin_lock_init(&new->create_lock);
        INIT_LIST_HEAD(&new->create_list);
        new->name = name;
+       new->flags = flags;
        task = kthread_run(kthreadd, new, name);
        if (IS_ERR(task)) {
                kfree(new);
@@ -314,7 +316,8 @@ int tsk_fork_get_node(struct task_struct *tsk)
        return NUMA_NO_NODE;
 }
 
-static void create_kthread(struct kthread_create_info *create)
+static void create_kthread(struct kthread_create_info *create,
+                          unsigned long flags)
 {
        int pid;
 
@@ -322,7 +325,7 @@ static void create_kthread(struct kthread_create_info 
*create)
        current->pref_node_fork = create->node;
 #endif
        /* We want our own signal handler (we take no signals by default). */
-       pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
+       pid = kernel_thread(kthread, create, flags);
        if (pid < 0) {
                /* If user was SIGKILLed, I release the structure. */
                struct completion *done = xchg(&create->done, NULL);
@@ -645,7 +648,7 @@ void kthread_do_work(struct kthread_group *kg)
                list_del_init(&create->list);
                spin_unlock(&kg->create_lock);
 
-               create_kthread(create);
+               create_kthread(create, kg->flags);
 
                spin_lock(&kg->create_lock);
        }
-- 
2.26.2