--- /dev/null
+From 166d3863231667c4f64dee72b77d1102cdfad11f Mon Sep 17 00:00:00 2001
+From: Demi Marie Obenour <demi@invisiblethingslab.com>
+Date: Sun, 10 Jul 2022 19:05:22 -0400
+Subject: xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE
+
+From: Demi Marie Obenour <demi@invisiblethingslab.com>
+
+commit 166d3863231667c4f64dee72b77d1102cdfad11f upstream.
+
+The error paths of gntdev_mmap() can call unmap_grant_pages() even
+though not all of the pages have been successfully mapped. This will
+trigger the WARN_ON()s in __unmap_grant_pages_done(). The number of
+warnings can be very large; I have observed thousands of lines of
+warnings in the systemd journal.
+
+Avoid this problem by only warning on unmapping failure if the handle
+being unmapped is not INVALID_GRANT_HANDLE. The handle field of any
+page that was not successfully mapped will be INVALID_GRANT_HANDLE, so
+this catches all cases where unmapping can legitimately fail.
+
+Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
+Cc: stable@vger.kernel.org
+Suggested-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
+Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
+Reviewed-by: Juergen Gross <jgross@suse.com>
+Link: https://lore.kernel.org/r/20220710230522.1563-1-demi@invisiblethingslab.com
+Signed-off-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/xen/gntdev.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/xen/gntdev.c
++++ b/drivers/xen/gntdev.c
+@@ -393,7 +393,8 @@ static void __unmap_grant_pages_done(int
+ unsigned int offset = data->unmap_ops - map->unmap_ops;
+
+ for (i = 0; i < data->count; i++) {
+- WARN_ON(map->unmap_ops[offset+i].status);
++ WARN_ON(map->unmap_ops[offset+i].status &&
++ map->unmap_ops[offset+i].handle != -1);
+ pr_debug("unmap handle=%d st=%d\n",
+ map->unmap_ops[offset+i].handle,
+ map->unmap_ops[offset+i].status);