Add a blurb that simply dirtying the folio will persist data for in-kernel shmem files. This is what most of the callers already do. Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx> --- mm/shmem.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index e89fb5eccb0c0a..f73dead491b11d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2148,6 +2148,10 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, * * If this function returns a folio, it is returned with an increased refcount. * + * If the caller modifies data in the folio, it must call folio_mark_dirty() + * before unlocking the folio to ensure that the folio is not reclaimed. + * These is no need to reserve space before calling folio_mark_dirty(). + * * Return: The found folio, %NULL if SGP_READ or SGP_NOALLOC was passed in @sgp * and no folio was found at @index, or an ERR_PTR() otherwise. */ -- 2.39.2
