From e91b48162332480f5840902268108bb7fb7a44c7 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 30 Jun 2020 17:32:54 +0200 Subject: task_work: teach task_work_add() to do signal_wake_up() So that the target task will exit the wait_event_interruptible-like loop and call task_work_run() asap. The patch turns "bool notify" into 0,TWA_RESUME,TWA_SIGNAL enum, the new TWA_SIGNAL flag implies signal_wake_up(). However, it needs to avoid the race with recalc_sigpending(), so the patch also adds the new JOBCTL_TASK_WORK bit included in JOBCTL_PENDING_MASK. TODO: once this patch is merged we need to change all current users of task_work_add(notify = true) to use TWA_RESUME. Cc: stable@vger.kernel.org # v5.7 Acked-by: Peter Zijlstra (Intel) Signed-off-by: Oleg Nesterov Signed-off-by: Jens Axboe --- include/linux/sched/jobctl.h | 4 +++- include/linux/task_work.h | 5 ++++- 2 files changed, 7 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/sched/jobctl.h b/include/linux/sched/jobctl.h index fa067de9f1a9..d2b4204ba4d3 100644 --- a/include/linux/sched/jobctl.h +++ b/include/linux/sched/jobctl.h @@ -19,6 +19,7 @@ struct task_struct; #define JOBCTL_TRAPPING_BIT 21 /* switching to TRACED */ #define JOBCTL_LISTENING_BIT 22 /* ptracer is listening for events */ #define JOBCTL_TRAP_FREEZE_BIT 23 /* trap for cgroup freezer */ +#define JOBCTL_TASK_WORK_BIT 24 /* set by TWA_SIGNAL */ #define JOBCTL_STOP_DEQUEUED (1UL << JOBCTL_STOP_DEQUEUED_BIT) #define JOBCTL_STOP_PENDING (1UL << JOBCTL_STOP_PENDING_BIT) @@ -28,9 +29,10 @@ struct task_struct; #define JOBCTL_TRAPPING (1UL << JOBCTL_TRAPPING_BIT) #define JOBCTL_LISTENING (1UL << JOBCTL_LISTENING_BIT) #define JOBCTL_TRAP_FREEZE (1UL << JOBCTL_TRAP_FREEZE_BIT) +#define JOBCTL_TASK_WORK (1UL << JOBCTL_TASK_WORK_BIT) #define JOBCTL_TRAP_MASK (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY) -#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK) +#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK | JOBCTL_TASK_WORK) extern bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask); extern void task_clear_jobctl_trapping(struct task_struct *task); diff --git a/include/linux/task_work.h b/include/linux/task_work.h index bd9a6a91c097..0fb93aafa478 100644 --- a/include/linux/task_work.h +++ b/include/linux/task_work.h @@ -13,7 +13,10 @@ init_task_work(struct callback_head *twork, task_work_func_t func) twork->func = func; } -int task_work_add(struct task_struct *task, struct callback_head *twork, bool); +#define TWA_RESUME 1 +#define TWA_SIGNAL 2 +int task_work_add(struct task_struct *task, struct callback_head *twork, int); + struct callback_head *task_work_cancel(struct task_struct *, task_work_func_t); void task_work_run(void); -- cgit v1.2.3