FAILED: patch "[PATCH] io_uring: correct pinned_vm accounting" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-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>.

Possible dependencies:

42b6419d0aba ("io_uring: correct pinned_vm accounting")
ed29b0b4fd83 ("io_uring: move to separate directory")
ab4094024784 ("io_uring: optimise rsrc referencing")
a46be971edb6 ("io_uring: optimise io_req_set_rsrc_node()")
d886e185a128 ("io_uring: control ->async_data with a REQ_F flag")
ef05d9ebcc92 ("io_uring: kill off ->inflight_entry field")
d4b7a5ef2b9c ("io_uring: inline completion batching helpers")
3aa83bfb6e5c ("io_uring: add a helper for batch free")
c2b6c6bc4e0d ("io_uring: replace list with stack for req caches")
3ab665b74e59 ("io_uring: remove allocation cache array")
6f33b0bc4ea4 ("io_uring: use slist for completion batching")
c450178d9be9 ("io_uring: dedup CQE flushing non-empty checks")
4b628aeb69cc ("io_uring: kill off ios_left")
4c928904ff77 ("block: move CONFIG_BLOCK guard to top Makefile")

thanks,

greg k-h

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

From 42b6419d0aba47c5d8644cdc0b68502254671de5 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 4 Oct 2022 03:19:08 +0100
Subject: [PATCH] io_uring: correct pinned_vm accounting

->mm_account should be released only after we free all registered
buffers, otherwise __io_sqe_buffers_unregister() will see a NULL
->mm_account and skip locked_vm accounting.

Cc: <Stable@vger.kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6d798f65ed4ab8db3664c4d3397d4af16ca98846.1664849932.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 63f6ce5e5355..ea5cee593bbd 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2585,12 +2585,6 @@ static void io_req_caches_free(struct io_ring_ctx *ctx)
 static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 {
 	io_sq_thread_finish(ctx);
-
-	if (ctx->mm_account) {
-		mmdrop(ctx->mm_account);
-		ctx->mm_account = NULL;
-	}
-
 	io_rsrc_refs_drop(ctx);
 	/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
 	io_wait_rsrc_data(ctx->buf_data);
@@ -2633,6 +2627,10 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 	WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
 	WARN_ON_ONCE(ctx->notif_slots || ctx->nr_notif_slots);
 
+	if (ctx->mm_account) {
+		mmdrop(ctx->mm_account);
+		ctx->mm_account = NULL;
+	}
 	io_mem_free(ctx->rings);
 	io_mem_free(ctx->sq_sqes);