[PATCH 2/4] task_work: kill current->task_works checking in callers

[Jens Axboe <axboe@kernel.dk>]

If the callsite cares, use task_work_pending(). If not, just call
task_work_run() unconditionally, that makes the check inline and
doesn't add any extra overhead.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io-wq.c                |  7 ++-----
 fs/io_uring.c             | 20 ++++++++------------
 include/linux/tracehook.h |  3 +--
 kernel/signal.c           |  7 +++----
 4 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 4023c9846860..5bee3f5f67e1 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -717,8 +717,7 @@ static int io_wq_manager(void *data)
 	complete(&wq->done);
 
 	while (!kthread_should_stop()) {
-		if (current->task_works)
-			task_work_run();
+		task_work_run();
 
 		for_each_node(node) {
 			struct io_wqe *wqe = wq->wqes[node];
@@ -742,9 +741,7 @@ static int io_wq_manager(void *data)
 		schedule_timeout(HZ);
 	}
 
-	if (current->task_works)
-		task_work_run();
-
+	task_work_run();
 	return 0;
 err:
 	set_bit(IO_WQ_BIT_ERROR, &wq->state);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 773f55c49cd8..7fb51c383e51 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5964,8 +5964,7 @@ static int io_sq_thread(void *data)
 			if (!list_empty(&ctx->poll_list) ||
 			    (!time_after(jiffies, timeout) && ret != -EBUSY &&
 			    !percpu_ref_is_dying(&ctx->refs))) {
-				if (current->task_works)
-					task_work_run();
+				task_work_run();
 				cond_resched();
 				continue;
 			}
@@ -5997,8 +5996,8 @@ static int io_sq_thread(void *data)
 					finish_wait(&ctx->sqo_wait, &wait);
 					break;
 				}
-				if (current->task_works) {
-					task_work_run();
+				if (task_work_pending()) {
+					__task_work_run();
 					finish_wait(&ctx->sqo_wait, &wait);
 					continue;
 				}
@@ -6021,8 +6020,7 @@ static int io_sq_thread(void *data)
 		timeout = jiffies + ctx->sq_thread_idle;
 	}
 
-	if (current->task_works)
-		task_work_run();
+	task_work_run();
 
 	set_fs(old_fs);
 	if (cur_mm) {
@@ -6091,9 +6089,9 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	do {
 		if (io_cqring_events(ctx, false) >= min_events)
 			return 0;
-		if (!current->task_works)
+		if (!task_work_pending())
 			break;
-		task_work_run();
+		__task_work_run();
 	} while (1);
 
 	if (sig) {
@@ -6114,8 +6112,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	do {
 		prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
 						TASK_INTERRUPTIBLE);
-		if (current->task_works)
-			task_work_run();
+		task_work_run();
 		if (io_should_wake(&iowq, false))
 			break;
 		schedule();
@@ -7465,8 +7462,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 	int submitted = 0;
 	struct fd f;
 
-	if (current->task_works)
-		task_work_run();
+	task_work_run();
 
 	if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
 		return -EINVAL;
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 36fb3bbed6b2..608a2d12bc14 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -184,8 +184,7 @@ 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))
-		task_work_run();
+	task_work_run();
 
 #ifdef CONFIG_KEYS_REQUEST_CACHE
 	if (unlikely(current->cached_requested_key)) {
diff --git a/kernel/signal.c b/kernel/signal.c
index 5b2396350dd1..e927cfae3151 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2271,8 +2271,8 @@ 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))
-		task_work_run();
+
+	task_work_run();
 
 	spin_lock_irq(&current->sighand->siglock);
 	ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
@@ -2529,8 +2529,7 @@ bool get_signal(struct ksignal *ksig)
 	struct signal_struct *signal = current->signal;
 	int signr;
 
-	if (unlikely(current->task_works))
-		task_work_run();
+	task_work_run();
 
 	if (unlikely(uprobe_deny_signal()))
 		return false;
-- 
2.26.0