FAILED: patch "[PATCH] io_uring: handle TIF_NOTIFY_RESUME when checking for" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x b5d3ae202fbfe055aa2a8ae8524531ee1dcab717
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

b5d3ae202fbf ("io_uring: handle TIF_NOTIFY_RESUME when checking for task_work") 7cfe7a09489c ("io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not available") 46a525e199e4 ("io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL") c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
b4c98d59a787 ("io_uring: introduce io_has_work")
78a861b94959 ("io_uring: add sync cancelation API through io_uring_register()") c34398a8c018 ("io_uring: remove __io_req_task_work_add")
ed5ccb3beeba ("io_uring: remove priority tw list optimisation") 625d38b3fd34 ("io_uring: improve io_run_task_work()")
4a0fef62788b ("io_uring: optimize io_uring_task layout")
253993210bd8 ("io_uring: introduce locking helpers for CQE posting") 305bef988708 ("io_uring: hide eventfd assumptions in eventfd paths") affa87db9010 ("io_uring: fix multi ctx cancellation")
d9dee4302a7c ("io_uring: remove ->flush_cqes optimisation") a830ffd28780 ("io_uring: move io_eventfd_signal()")
9046c6415be6 ("io_uring: reshuffle io_uring/io_uring.h")
d142c3ec8d16 ("io_uring: remove extra io_commit_cqring()")
ab1c84d855cf ("io_uring: make io_uring_types.h public")
68494a65d0e2 ("io_uring: introduce io_req_cqe_overflow()")
faf88dde060f ("io_uring: don't inline __io_get_cqe()")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b5d3ae202fbfe055aa2a8ae8524531ee1dcab717 Mon Sep 17 00:00:00 2001
From: Jens Axboe <[email protected]>
Date: Tue, 24 Jan 2023 08:24:25 -0700
Subject: [PATCH] io_uring: handle TIF_NOTIFY_RESUME when checking for
task_work

If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work() for PF_IO_WORKER threads. They never return to usermode, hence never get a chance to process any items that are marked by this flag. Most notably this includes the final put of files, but also any throttling markers set by block cgroups.

index c68edf9872a5..d58cfe062da9 100644
@@ -3,6 +3,7 @@
 
 #include <linux/errno.h>
 #include <linux/lockdep.h>
+#include <linux/resume_user_mode.h>
 #include <linux/io_uring_types.h>
 #include <uapi/linux/eventpoll.h>
 #include "io-wq.h"

@@ -274,6 +275,13 @@ static inline int io_run_task_work(void)
 	 */
 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 		clear_notify_signal();
+	/*
+	 * PF_IO_WORKER never returns to userspace, so check here if we have
+	 * notify work that needs processing.
+	 */
+	if (current->flags & PF_IO_WORKER &&
+	    test_thread_flag(TIF_NOTIFY_RESUME))
+		resume_user_mode_work(NULL);
 	if (task_work_pending(current)) {
 		__set_current_state(TASK_RUNNING);
 		task_work_run();