6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christoph Hellwig <hch@xxxxxx>
commit 54e7d59841dab977f6cb1183d658b1b82c9f4e94 upstream.
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.
[v-songbaohua@xxxxxxxx: figure out the cause and correct the commit message]
Link: https://lkml.kernel.org/r/20240618065647.21791-1-21cnbao@xxxxxxxxx
Fixes: 2282679fb20b ("mm: submit multipage write for SWP_FS_OPS swap-space")
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Closes: https://lore.kernel.org/linux-mm/20240617053201.GA16852@xxxxxx/
Reviewed-by: Martin Wege <martin.l.wege@xxxxxxxxx>
Cc: NeilBrown <neilb@xxxxxxx>
Cc: Anna Schumaker <anna@xxxxxxxxxx>
Cc: Steve French <sfrench@xxxxxxxxx>
Cc: Trond Myklebust <trondmy@xxxxxxxxxx>
Cc: Chuanhua Han <hanchuanhua@xxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/direct.c | 2 --
1 file changed, 2 deletions(-)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -141,8 +141,6 @@ int nfs_swap_rw(struct kiocb *iocb, stru
{
ssize_t ret;
- VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
-
if (iov_iter_rw(iter) == READ)
ret = nfs_file_direct_read(iocb, iter, true);
else
