FAILED: patch "[PATCH] cifs: drop the incorrect assertion in cifs_swap_rw()" failed to apply to 6.9-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.9-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>.

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-6.9.y
git checkout FETCH_HEAD
git cherry-pick -x 29433a17a79caa8680b9c0761f2b10502fda9ce3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024062428-captivate-grasp-a4cf@gregkh' --subject-prefix 'PATCH 6.9.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 29433a17a79caa8680b9c0761f2b10502fda9ce3 Mon Sep 17 00:00:00 2001
From: Barry Song <baohua@kernel.org>
Date: Tue, 18 Jun 2024 19:22:58 +1200
Subject: [PATCH] cifs: drop the incorrect assertion in cifs_swap_rw()

Since commit 2282679fb20b ("mm: submit multipage write for SWP_FS_OPS
swap-space"), we can plug multiple pages then unplug them all together.
That means iov_iter_count(iter) could be way bigger than PAGE_SIZE, it
actually equals the size of iov_iter_npages(iter, INT_MAX).

Note this issue has nothing to do with large folios as we don't support
THP_SWPOUT to non-block devices.

Fixes: 2282679fb20b ("mm: submit multipage write for SWP_FS_OPS swap-space")
Reported-by: Christoph Hellwig <hch@lst.de>
Closes: https://lore.kernel.org/linux-mm/20240614100329.1203579-1-hch@lst.de/
Cc: NeilBrown <neilb@suse.de>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Steve French <sfrench@samba.org>
Cc: Trond Myklebust <trondmy@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Paulo Alcantara <pc@manguebit.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 9d5c2440abfc..1e269e0bc75b 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -3200,8 +3200,6 @@ static int cifs_swap_rw(struct kiocb *iocb, struct iov_iter *iter)
 {
 	ssize_t ret;
 
-	WARN_ON_ONCE(iov_iter_count(iter) != PAGE_SIZE);
-
 	if (iov_iter_rw(iter) == READ)
 		ret = netfs_unbuffered_read_iter_locked(iocb, iter);
 	else