task_work: cleanup notification modes

A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.

Clean this up properly, and define a proper enum for the notification
mode. Now we have:

- TWA_NONE. This is 0, same as before the original change, meaning no
  notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
  that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
  notification.

Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.

Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 9 insertions, 8 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 656647f9575a..709ada3151da 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -339,7 +339,7 @@ void fput_many(struct file *file, unsigned int refs)
 
 		if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
 			init_task_work(&file->f_u.fu_rcuhead, ____fput);
-			if (!task_work_add(task, &file->f_u.fu_rcuhead, true))
+			if (!task_work_add(task, &file->f_u.fu_rcuhead, TWA_RESUME))
 				return;
 			/*
 			 * After this task has run exit_task_work(),
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e1726f457461..6b502885684a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1976,7 +1976,8 @@ static int io_req_task_work_add(struct io_kiocb *req, bool twa_signal_ok)
 {
 	struct task_struct *tsk = req->task;
 	struct io_ring_ctx *ctx = req->ctx;
-	int ret, notify;
+	enum task_work_notify_mode notify;
+	int ret;
 
 	if (tsk->flags & PF_EXITING)
 		return -ESRCH;
@@ -1987,7 +1988,7 @@ static int io_req_task_work_add(struct io_kiocb *req, bool twa_signal_ok)
 	 * processing task_work. There's no reliable way to tell if TWA_RESUME
 	 * will do the job.
 	 */
-	notify = 0;
+	notify = TWA_NONE;
 	if (!(ctx->flags & IORING_SETUP_SQPOLL) && twa_signal_ok)
 		notify = TWA_SIGNAL;
 
@@ -2056,7 +2057,7 @@ static void io_req_task_queue(struct io_kiocb *req)
 
 		init_task_work(&req->task_work, io_req_task_cancel);
 		tsk = io_wq_get_task(req->ctx->io_wq);
-		task_work_add(tsk, &req->task_work, 0);
+		task_work_add(tsk, &req->task_work, TWA_NONE);
 		wake_up_process(tsk);
 	}
 }
@@ -2177,7 +2178,7 @@ static void io_free_req_deferred(struct io_kiocb *req)
 		struct task_struct *tsk;
 
 		tsk = io_wq_get_task(req->ctx->io_wq);
-		task_work_add(tsk, &req->task_work, 0);
+		task_work_add(tsk, &req->task_work, TWA_NONE);
 		wake_up_process(tsk);
 	}
 }
@@ -3291,7 +3292,7 @@ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
 		/* queue just for cancelation */
 		init_task_work(&req->task_work, io_req_task_cancel);
 		tsk = io_wq_get_task(req->ctx->io_wq);
-		task_work_add(tsk, &req->task_work, 0);
+		task_work_add(tsk, &req->task_work, TWA_NONE);
 		wake_up_process(tsk);
 	}
 	return 1;
@@ -4857,7 +4858,7 @@ static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
 
 		WRITE_ONCE(poll->canceled, true);
 		tsk = io_wq_get_task(req->ctx->io_wq);
-		task_work_add(tsk, &req->task_work, 0);
+		task_work_add(tsk, &req->task_work, TWA_NONE);
 		wake_up_process(tsk);
 	}
 	return 1;
diff --git a/fs/namespace.c b/fs/namespace.c
index 294e05a13d17..1a75336668a3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1191,7 +1191,7 @@ static void mntput_no_expire(struct mount *mnt)
 		struct task_struct *task = current;
 		if (likely(!(task->flags & PF_KTHREAD))) {
 			init_task_work(&mnt->mnt_rcu, __cleanup_mnt);
-			if (!task_work_add(task, &mnt->mnt_rcu, true))
+			if (!task_work_add(task, &mnt->mnt_rcu, TWA_RESUME))
 				return;
 		}
 		if (llist_add(&mnt->mnt_llist, &delayed_mntput_list))