FAILED: patch "[PATCH] io_uring: drop mm/files between task_work_submit" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] io_uring: drop mm/files between task_work_submit" failed to apply to 5.10-stable tree

[gregkh]

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 <stable@vger.kernel.org>.

thanks,

greg k-h

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

From aec18a57edad562d620f7d19016de1fc0cc2208c Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Thu, 4 Feb 2021 19:22:46 +0000
Subject: [PATCH] io_uring: drop mm/files between task_work_submit

Since SQPOLL task can be shared and so task_work entries can be a mix of
them, we need to drop mm and files before trying to issue next request.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5d3348d66f06..1f68105a41ed 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2205,6 +2205,9 @@ static void __io_req_task_submit(struct io_kiocb *req)
 	else
 		__io_req_task_cancel(req, -EFAULT);
 	mutex_unlock(&ctx->uring_lock);
+
+	if (ctx->flags & IORING_SETUP_SQPOLL)
+		io_sq_thread_drop_mm_files();
 }
 
 static void io_req_task_submit(struct callback_head *cb)