The patch titled
Subject: genirq: reimplement exit_irq_thread() hook via task_work_add()
has been removed from the -mm tree. Its filename was
genirq-reimplement-exit_irq_thread-hook-via-task_work_add.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: genirq: reimplement exit_irq_thread() hook via task_work_add()
exit_irq_thread() and task->irq_thread are needed to handle the unexpected
(and unlikely) exit of irq-thread.
We can use task_work instead and make this all private to
kernel/irq/manage.c, cleanup plus micro-optimization.
1. rename exit_irq_thread() to irq_thread_dtor(), make it
static, and move it up before irq_thread().
2. change irq_thread() to do task_work_add(irq_thread_dtor)
at the start and task_work_cancel() before return.
tracehook_notify_resume() can never play with kthreads,
only do_exit()->exit_task_work() can call the callback
and this is what we want.
3. remove task_struct->irq_thread and the special hook
in do_exit().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Richard Kuo <rkuo@xxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: David Smith <dsmith@xxxxxxxxxx>
Cc: "Frank Ch. Eigler" <fche@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Larry Woodman <lwoodman@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/interrupt.h | 4 --
include/linux/sched.h | 10 +----
kernel/exit.c | 2 -
kernel/irq/manage.c | 68 +++++++++++++++++-------------------
4 files changed, 35 insertions(+), 49 deletions(-)
diff -puN include/linux/interrupt.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add include/linux/interrupt.h
--- a/include/linux/interrupt.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add
+++ a/include/linux/interrupt.h
@@ -142,8 +142,6 @@ request_any_context_irq(unsigned int irq
extern int __must_check
request_percpu_irq(unsigned int irq, irq_handler_t handler,
const char *devname, void __percpu *percpu_dev_id);
-
-extern void exit_irq_thread(void);
#else
extern int __must_check
@@ -177,8 +175,6 @@ request_percpu_irq(unsigned int irq, irq
{
return request_irq(irq, handler, 0, devname, percpu_dev_id);
}
-
-static inline void exit_irq_thread(void) { }
#endif
extern void free_irq(unsigned int, void *);
diff -puN include/linux/sched.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add include/linux/sched.h
--- a/include/linux/sched.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add
+++ a/include/linux/sched.h
@@ -1357,11 +1357,6 @@ struct task_struct {
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
-#ifdef CONFIG_GENERIC_HARDIRQS
- /* IRQ handler threads */
- unsigned irq_thread:1;
-#endif
-
pid_t pid;
pid_t tgid;
@@ -1369,10 +1364,9 @@ struct task_struct {
/* Canary value for the -fstack-protector gcc feature */
unsigned long stack_canary;
#endif
-
- /*
+ /*
* pointers to (original) parent process, youngest child, younger sibling,
- * older sibling, respectively. (p->father can be replaced with
+ * older sibling, respectively. (p->father can be replaced with
* p->real_parent->pid)
*/
struct task_struct __rcu *real_parent; /* real parent process */
diff -puN kernel/exit.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add kernel/exit.c
--- a/kernel/exit.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add
+++ a/kernel/exit.c
@@ -954,8 +954,6 @@ void do_exit(long code)
exit_task_work(tsk);
- exit_irq_thread();
-
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
diff -puN kernel/irq/manage.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add kernel/irq/manage.c
--- a/kernel/irq/manage.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add
+++ a/kernel/irq/manage.c
@@ -14,6 +14,7 @@
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/sched.h>
+#include <linux/task_work.h>
#include "internals.h"
@@ -773,11 +774,39 @@ static void wake_threads_waitq(struct ir
wake_up(&desc->wait_for_threads);
}
+static void irq_thread_dtor(struct task_work *unused)
+{
+ struct task_struct *tsk = current;
+ struct irq_desc *desc;
+ struct irqaction *action;
+
+ if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+ return;
+
+ action = kthread_data(tsk);
+
+ pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+ tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
+
+
+ desc = irq_to_desc(action->irq);
+ /*
+ * If IRQTF_RUNTHREAD is set, we need to decrement
+ * desc->threads_active and wake possible waiters.
+ */
+ if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+ wake_threads_waitq(desc);
+
+ /* Prevent a stale desc->threads_oneshot */
+ irq_finalize_oneshot(desc, action);
+}
+
/*
* Interrupt handler thread
*/
static int irq_thread(void *data)
{
+ struct task_work on_exit_work;
static const struct sched_param param = {
.sched_priority = MAX_USER_RT_PRIO/2,
};
@@ -793,7 +822,9 @@ static int irq_thread(void *data)
handler_fn = irq_thread_fn;
sched_setscheduler(current, SCHED_FIFO, ¶m);
- current->irq_thread = 1;
+
+ init_task_work(&on_exit_work, irq_thread_dtor, NULL);
+ task_work_add(current, &on_exit_work, false);
while (!irq_wait_for_interrupt(action)) {
irqreturn_t action_ret;
@@ -815,44 +846,11 @@ static int irq_thread(void *data)
* cannot touch the oneshot mask at this point anymore as
* __setup_irq() might have given out currents thread_mask
* again.
- *
- * Clear irq_thread. Otherwise exit_irq_thread() would make
- * fuzz about an active irq thread going into nirvana.
*/
- current->irq_thread = 0;
+ task_work_cancel(current, irq_thread_dtor);
return 0;
}
-/*
- * Called from do_exit()
- */
-void exit_irq_thread(void)
-{
- struct task_struct *tsk = current;
- struct irq_desc *desc;
- struct irqaction *action;
-
- if (!tsk->irq_thread)
- return;
-
- action = kthread_data(tsk);
-
- pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
- tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
-
- desc = irq_to_desc(action->irq);
-
- /*
- * If IRQTF_RUNTHREAD is set, we need to decrement
- * desc->threads_active and wake possible waiters.
- */
- if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
- wake_threads_waitq(desc);
-
- /* Prevent a stale desc->threads_oneshot */
- irq_finalize_oneshot(desc, action);
-}
-
static void irq_setup_forced_threading(struct irqaction *new)
{
if (!force_irqthreads)
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
mm-fork-fix-overflow-in-vma-length-when-copying-mmap-on-clone.patch
mm-correctly-synchronize-rss-counters-at-exit-exec.patch
kmod-unexport-call_usermodehelper_freeinfo.patch
kmod-convert-two-call-sites-to-call_usermodehelper_fns.patch
kmod-move-call_usermodehelper_fns-to-c-file-and-unexport-all-its-helpers.patch
cred-remove-task_is_dead-from-__task_cred-validation.patch
stack-usage-add-pid-to-warning-printk-in-check_stack_usage.patch
proc-clean-up-proc-pid-environ-handling.patch
proc-remove-mm_for_maps.patch
proc-use-mm_access-instead-of-ptrace_may_access.patch
proc-use-is_err_or_null.patch
fork-call-complete_vfork_done-after-clearing-child_tid-and-flushing-rss-counters.patch
cpu-introduce-clear_tasks_mm_cpumask-helper.patch
arm-use-clear_tasks_mm_cpumask.patch
powerpc-use-clear_tasks_mm_cpumask.patch
sh-use-clear_tasks_mm_cpumask.patch
blackfin-a-couple-of-task-mm-handling-fixes.patch
blackfin-fix-possible-deadlock-in-decode_address.patch
um-should-hold-tasklist_lock-while-traversing-processes.patch
um-fix-possible-race-on-task-mm.patch
um-properly-check-all-process-threads-for-a-live-mm.patch
pidns-use-task_active_pid_ns-in-do_notify_parent.patch
pidns-make-killed-children-autoreap.patch
pidns-guarantee-that-the-pidns-init-will-be-the-last-pidns-process-reaped-v2.patch
pidns-guarantee-that-the-pidns-init-will-be-the-last-pidns-process-reaped-v2-fix.patch
aio-vfs-cleanup-of-rw_copy_check_uvector-and-compat_rw_copy_check_uvector.patch
sysctl-make-kernelns_last_pid-control-being-checkpoint_restore-dependent.patch
fs-proc-introduce-proc-pid-task-tid-children-entry-v9.patch
fs-proc-introduce-proc-pid-task-tid-children-entry-v9-fix.patch
c-r-prctl-add-ability-to-set-new-mm_struct-exe_file.patch
c-r-prctl-add-ability-to-set-new-mm_struct-exe_file-update-after-mm-num_exe_file_vmas-removal.patch
c-r-prctl-add-ability-to-get-clear_tid_address.patch
c-r-prctl-drop-vma-flags-test-on-pr_set_mm_-stack-data-assignment.patch
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