[PATCH 07/13] task_work: Introduce task_work_pending

Eric W. Biederman
2022-03-09T16:44:26Z

Wrap the test of task->task_works in a helper function to make
it clear what is being tested.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/io_uring.c | 6 +++---
include/linux/task_work.h | 5 +++++
include/linux/tracehook.h | 4 ++--
kernel/signal.c | 4 ++--
kernel/task_work.c | 2 +-
5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e54c4127422e..e85261079a78 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2590,7 +2590,7 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)

static inline bool io_run_task_work(void)
{
- if (test_thread_flag(TIF_NOTIFY_SIGNAL) || current->task_works) {
+ if (test_thread_flag(TIF_NOTIFY_SIGNAL) || task_work_pending(current)) {
__set_current_state(TASK_RUNNING);
tracehook_notify_signal();
return true;
@@ -7602,7 +7602,7 @@ static int io_sq_thread(void *data)
}

prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
- if (!io_sqd_events_pending(sqd) && !current->task_works) {
+ if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) {
bool needs_sched = true;

list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
@@ -10321,7 +10321,7 @@ static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx,

hlist_for_each_entry(req, list, hash_node)
seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
- req->task->task_works != NULL);
+ task_work_pending(req->task));
}

seq_puts(m, "CqOverflowList:\n");
diff --git a/include/linux/task_work.h b/include/linux/task_work.h
index 5b8a93f288bb..897494b597ba 100644
--- a/include/linux/task_work.h
+++ b/include/linux/task_work.h
@@ -19,6 +19,11 @@ enum task_work_notify_mode {
TWA_SIGNAL,
};

+static inline bool task_work_pending(struct task_struct *task)
+{
+ return READ_ONCE(task->task_works);
+}
+
int task_work_add(struct task_struct *task, struct callback_head *twork,
enum task_work_notify_mode mode);

diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index b77bf4917196..fa834a22e86e 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -90,7 +90,7 @@ static inline void tracehook_notify_resume(struct pt_regs *regs)
* hlist_add_head(task->task_works);
*/
smp_mb__after_atomic();
- if (unlikely(current->task_works))
+ if (unlikely(task_work_pending(current)))
task_work_run();

#ifdef CONFIG_KEYS_REQUEST_CACHE
@@ -115,7 +115,7 @@ static inline void tracehook_notify_signal(void)
{
clear_thread_flag(TIF_NOTIFY_SIGNAL);
smp_mb__after_atomic();
- if (current->task_works)
+ if (task_work_pending(current))
task_work_run();
}

diff --git a/kernel/signal.c b/kernel/signal.c
index 0e0bd1c1068b..3b4cf25fb9b3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2344,7 +2344,7 @@ static void ptrace_do_notify(int signr, int exit_code, int why)
void ptrace_notify(int exit_code)
{
BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
- if (unlikely(current->task_works))
+ if (unlikely(task_work_pending(current)))
task_work_run();

spin_lock_irq(&current->sighand->siglock);
@@ -2626,7 +2626,7 @@ bool get_signal(struct ksignal *ksig)
struct signal_struct *signal = current->signal;
int signr;

- if (unlikely(current->task_works))
+ if (unlikely(task_work_pending(current)))
task_work_run();

/*
diff --git a/kernel/task_work.c b/kernel/task_work.c
index 1698fbe6f0e1..cc6fccb0e24d 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -78,7 +78,7 @@ task_work_cancel_match(struct task_struct *task,
struct callback_head *work;
unsigned long flags;

- if (likely(!task->task_works))
+ if (likely(!task_work_pending(task)))
return NULL;
/*
* If cmpxchg() fails we continue without updating pprev.
--
2.29.2