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authorEric W. Biederman <ebiederm@xmission.com>2021-12-23 07:10:09 +0300
committerEric W. Biederman <ebiederm@xmission.com>2022-01-08 18:39:49 +0300
commite32cf5dfbe227b355776948b2c9b5691b84d1cbd (patch)
treec00df29e5a3bf47010fbdf5e5dbaa20325b7d1a6 /kernel/fork.c
parent00580f03af5eb2a527875b4a80a5effd95bda2fa (diff)
downloadlinux-e32cf5dfbe227b355776948b2c9b5691b84d1cbd.tar.xz
kthread: Generalize pf_io_worker so it can point to struct kthread
The point of using set_child_tid to hold the kthread pointer was that it already did what is necessary. There are now restrictions on when set_child_tid can be initialized and when set_child_tid can be used in schedule_tail. Which indicates that continuing to use set_child_tid to hold the kthread pointer is a bad idea. Instead of continuing to use the set_child_tid field of task_struct generalize the pf_io_worker field of task_struct and use it to hold the kthread pointer. Rename pf_io_worker (which is a void * pointer) to worker_private so it can be used to store kthreads struct kthread pointer. Update the kthread code to store the kthread pointer in the worker_private field. Remove the places where set_child_tid had to be dealt with carefully because kthreads also used it. Link: https://lkml.kernel.org/r/CAHk-=wgtFAA9SbVYg0gR1tqPMC17-NYcs0GQkaYg1bGhh1uJQQ@mail.gmail.com Link: https://lkml.kernel.org/r/87a6grvqy8.fsf_-_@email.froward.int.ebiederm.org Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 0816be1bb044..6f0293cb29c9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -950,7 +950,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->splice_pipe = NULL;
tsk->task_frag.page = NULL;
tsk->wake_q.next = NULL;
- tsk->pf_io_worker = NULL;
+ tsk->worker_private = NULL;
account_kernel_stack(tsk, 1);
@@ -2032,12 +2032,6 @@ static __latent_entropy struct task_struct *copy_process(
siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
}
- /*
- * This _must_ happen before we call free_task(), i.e. before we jump
- * to any of the bad_fork_* labels. This is to avoid freeing
- * p->set_child_tid which is (ab)used as a kthread's data pointer for
- * kernel threads (PF_KTHREAD).
- */
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
/*
* Clear TID on mm_release()?