The patch titled
Subject: kthread: kill task_get_live_kthread()
has been removed from the -mm tree. Its filename was
kthread-kill-task_get_live_kthread.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: kthread: kill task_get_live_kthread()
task_get_live_kthread() looks confusing and unneeded. It does
get_task_struct() but only kthread_stop() needs this, it can be called
even if the calller doesn't have a reference when we know that this
kthread can't exit until we do kthread_stop().
kthread_park() and kthread_unpark() do not need get_task_struct(), the
callers already have the reference. And it can not help if we can race
with the exiting kthread anyway, kthread_park() can hang forever in this
case.
Change kthread_park() and kthread_unpark() to use to_live_kthread(),
change kthread_stop() to do get_task_struct() by hand and remove
task_get_live_kthread().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kthread.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff -puN kernel/kthread.c~kthread-kill-task_get_live_kthread kernel/kthread.c
--- a/kernel/kthread.c~kthread-kill-task_get_live_kthread
+++ a/kernel/kthread.c
@@ -324,12 +324,6 @@ struct task_struct *kthread_create_on_cp
return p;
}
-static struct kthread *task_get_live_kthread(struct task_struct *k)
-{
- get_task_struct(k);
- return to_live_kthread(k);
-}
-
static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
{
clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
@@ -356,11 +350,10 @@ static void __kthread_unpark(struct task
*/
void kthread_unpark(struct task_struct *k)
{
- struct kthread *kthread = task_get_live_kthread(k);
+ struct kthread *kthread = to_live_kthread(k);
if (kthread)
__kthread_unpark(k, kthread);
- put_task_struct(k);
}
/**
@@ -377,7 +370,7 @@ void kthread_unpark(struct task_struct *
*/
int kthread_park(struct task_struct *k)
{
- struct kthread *kthread = task_get_live_kthread(k);
+ struct kthread *kthread = to_live_kthread(k);
int ret = -ENOSYS;
if (kthread) {
@@ -390,7 +383,6 @@ int kthread_park(struct task_struct *k)
}
ret = 0;
}
- put_task_struct(k);
return ret;
}
@@ -411,10 +403,13 @@ int kthread_park(struct task_struct *k)
*/
int kthread_stop(struct task_struct *k)
{
- struct kthread *kthread = task_get_live_kthread(k);
+ struct kthread *kthread;
int ret;
trace_sched_kthread_stop(k);
+
+ get_task_struct(k);
+ kthread = to_live_kthread(k);
if (kthread) {
set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
__kthread_unpark(k, kthread);
@@ -422,10 +417,9 @@ int kthread_stop(struct task_struct *k)
wait_for_completion(&kthread->exited);
}
ret = k->exit_code;
-
put_task_struct(k);
- trace_sched_kthread_stop_ret(ret);
+ trace_sched_kthread_stop_ret(ret);
return ret;
}
EXPORT_SYMBOL(kthread_stop);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
posix_cpu_timer-consolidate-expiry-time-type.patch
posix_cpu_timers-consolidate-timer-list-cleanups.patch
posix_cpu_timers-consolidate-expired-timers-check.patch
posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch
posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
kthread-implement-probe_kthread_data.patch
workqueue-include-workqueue-info-when-printing-debug-dump-of-a-worker-task.patch
writeback-set-worker-desc-to-identify-writeback-workers-in-task-dumps.patch
kernel-smpc-use-=-for-csd_lock.patch
kernel-smpc-remove-priv-of-call_single_data.patch
epoll-use-rcu-to-protect-wakeup_source-in-epitem.patch
epoll-lock-ep-mtx-in-ep_free-to-silence-lockdep.patch
ptrace-add-ability-to-retrieve-signals-without-removing-from-a-queue-v4.patch
selftest-add-a-test-case-for-ptrace_peeksiginfo.patch
usermodehelper-export-_exec-and-_setup-functions.patch
usermodehelper-export-_exec-and-_setup-functions-fix.patch
kmod-split-call-to-call_usermodehelper_fns.patch
keys-split-call-to-call_usermodehelper_fns.patch
coredump-remove-trailling-whitespaces.patch
split-remaining-calls-to-call_usermodehelper_fns.patch
kmod-remove-call_usermodehelper_fns.patch
coredump-only-sigkill-should-interrupt-the-coredumping-task.patch
coredump-ensure-that-sigkill-always-kills-the-dumping-thread.patch
coredump-sanitize-the-setting-of-signal-group_exit_code.patch
coredump-introduce-dump_interrupted.patch
coredump-factor-out-the-setting-of-pf_dumpcore.patch
coredump-change-wait_for_dump_helpers-to-use-wait_event_interruptible.patch
set_task_comm-kill-the-pointless-memset-wmb.patch
exec-do-not-abuse-cred_guard_mutex-in-threadgroup_lock.patch
--
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