Merge branch 'for-5.19/io_uring' into for-5.19/io_uring-passthrough

* for-5.19/io_uring: (85 commits)
  io_uring: don't clear req->kbuf when buffer selection is done
  io_uring: eliminate the need to track provided buffer ID separately
  io_uring: move provided buffer state closer to submit state
  io_uring: move provided and fixed buffers into the same io_kiocb area
  io_uring: abstract out provided buffer list selection
  io_uring: never call io_buffer_select() for a buffer re-select
  io_uring: get rid of hashed provided buffer groups
  io_uring: always use req->buf_index for the provided buffer group
  io_uring: ignore ->buf_index if REQ_F_BUFFER_SELECT isn't set
  io_uring: kill io_rw_buffer_select() wrapper
  io_uring: make io_buffer_select() return the user address directly
  io_uring: kill io_recv_buffer_select() wrapper
  io_uring: use 'sr' vs 'req->sr_msg' consistently
  io_uring: add POLL_FIRST support for send/sendmsg and recv/recvmsg
  io_uring: check IOPOLL/ioprio support upfront
  io_uring: replace smp_mb() with smp_mb__after_atomic() in io_sq_thread()
  io_uring: add IORING_SETUP_TASKRUN_FLAG
  io_uring: use TWA_SIGNAL_NO_IPI if IORING_SETUP_COOP_TASKRUN is used
  io_uring: set task_work notify method at init time
  io-wq: use __set_notify_signal() to wake workers
  ...

1 files changed, 19 insertions, 6 deletions

diff --git a/kernel/task_work.c b/kernel/task_work.c
index c59e1a49bc40..dff75bcde151 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -12,12 +12,22 @@ static struct callback_head work_exited; /* all we need is ->next == NULL */
  * @notify: how to notify the targeted task
  *
  * Queue @work for task_work_run() below and notify the @task if @notify
- * is @TWA_RESUME or @TWA_SIGNAL. @TWA_SIGNAL works like signals, in that the
- * it will interrupt the targeted task and run the task_work. @TWA_RESUME
- * work is run only when the task exits the kernel and returns to user mode,
- * or before entering guest mode. Fails if the @task is exiting/exited and thus
- * it can't process this @work. Otherwise @work->func() will be called when the
- * @task goes through one of the aforementioned transitions, or exits.
+ * is @TWA_RESUME, @TWA_SIGNAL, or @TWA_SIGNAL_NO_IPI.
+ *
+ * @TWA_SIGNAL works like signals, in that the it will interrupt the targeted
+ * task and run the task_work, regardless of whether the task is currently
+ * running in the kernel or userspace.
+ * @TWA_SIGNAL_NO_IPI works like @TWA_SIGNAL, except it doesn't send a
+ * reschedule IPI to force the targeted task to reschedule and run task_work.
+ * This can be advantageous if there's no strict requirement that the
+ * task_work be run as soon as possible, just whenever the task enters the
+ * kernel anyway.
+ * @TWA_RESUME work is run only when the task exits the kernel and returns to
+ * user mode, or before entering guest mode.
+ *
+ * Fails if the @task is exiting/exited and thus it can't process this @work.
+ * Otherwise @work->func() will be called when the @task goes through one of
+ * the aforementioned transitions, or exits.
  *
  * If the targeted task is exiting, then an error is returned and the work item
  * is not queued. It's up to the caller to arrange for an alternative mechanism
@@ -53,6 +63,9 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
 	case TWA_SIGNAL:
 		set_notify_signal(task);
 		break;
+	case TWA_SIGNAL_NO_IPI:
+		__set_notify_signal(task);
+		break;
 	default:
 		WARN_ON_ONCE(1);
 		break;