[tip: core/entry] signal: Add task_sigpending() helper

tip-bot2 for Jens Axboe
2020-10-29T10:30:20Z

The following commit has been merged into the core/entry branch of tip:

Commit-ID: 5c251e9dc0e127bac6fc5b8e6696363d2e35f515
Gitweb: https://git.kernel.org/tip/5c251e9dc0e127bac6fc5b8e6696363d2e35f515
Author: Jens Axboe <axboe@kernel.dk>
AuthorDate: Mon, 26 Oct 2020 14:32:27 -06:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 29 Oct 2020 09:37:36 +01:00

signal: Add task_sigpending() helper

This is in preparation for maintaining signal_pending() as the decider of
whether or not a schedule() loop should be broken, or continue sleeping.
This is different than the core signal use cases, which really need to know
whether an actual signal is pending or not. task_sigpending() returns
non-zero if TIF_SIGPENDING is set.

Only core kernel use cases should care about the distinction between
the two, make sure those use the task_sigpending() helper.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20201026203230.386348-2-axboe@kernel.dk

---
include/linux/sched/signal.h | 9 +++++++--
kernel/events/uprobes.c | 2 +-
kernel/signal.c | 8 ++++----
3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 1bad18a..404145d 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -353,11 +353,16 @@ static inline int restart_syscall(void)
return -ERESTARTNOINTR;
}

-static inline int signal_pending(struct task_struct *p)
+static inline int task_sigpending(struct task_struct *p)
{
return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
}

+static inline int signal_pending(struct task_struct *p)
+{
+ return task_sigpending(p);
+}
+
static inline int __fatal_signal_pending(struct task_struct *p)
{
return unlikely(sigismember(&p->pending.signal, SIGKILL));
@@ -365,7 +370,7 @@ static inline int __fatal_signal_pending(struct task_struct *p)

static inline int fatal_signal_pending(struct task_struct *p)
{
- return signal_pending(p) && __fatal_signal_pending(p);
+ return task_sigpending(p) && __fatal_signal_pending(p);
}

static inline int signal_pending_state(long state, struct task_struct *p)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 649fd53..edd0c98 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1973,7 +1973,7 @@ bool uprobe_deny_signal(void)

WARN_ON_ONCE(utask->state != UTASK_SSTEP);

- if (signal_pending(t)) {
+ if (task_sigpending(t)) {
spin_lock_irq(&t->sighand->siglock);
clear_tsk_thread_flag(t, TIF_SIGPENDING);
spin_unlock_irq(&t->sighand->siglock);
diff --git a/kernel/signal.c b/kernel/signal.c
index 42b67d2..b179ecc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -983,7 +983,7 @@ static inline bool wants_signal(int sig, struct task_struct *p)
if (task_is_stopped_or_traced(p))
return false;

- return task_curr(p) || !signal_pending(p);
+ return task_curr(p) || !task_sigpending(p);
}

static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
@@ -2822,7 +2822,7 @@ static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
/* Remove the signals this thread can handle. */
sigandsets(&retarget, &retarget, &t->blocked);

- if (!signal_pending(t))
+ if (!task_sigpending(t))
signal_wake_up(t, 0);

if (sigisemptyset(&retarget))
@@ -2856,7 +2856,7 @@ void exit_signals(struct task_struct *tsk)

cgroup_threadgroup_change_end(tsk);

- if (!signal_pending(tsk))
+ if (!task_sigpending(tsk))
goto out;

unblocked = tsk->blocked;
@@ -2900,7 +2900,7 @@ long do_no_restart_syscall(struct restart_block *param)

static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
{
- if (signal_pending(tsk) && !thread_group_empty(tsk)) {
+ if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
sigset_t newblocked;
/* A set of now blocked but previously unblocked signals. */
sigandnsets(&newblocked, newset, &current->blocked);