Add some notes about how this function needs to be called. Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> --- mm/page-writeback.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index a613f8ef6a02..91d163f8d36b 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2496,7 +2496,11 @@ void folio_account_cleaned(struct folio *folio, struct address_space *mapping, * If warn is true, then emit a warning if the folio is not uptodate and has * not been truncated. * - * The caller must hold lock_page_memcg(). + * The caller must hold lock_page_memcg(). Most callers have the folio + * locked. A few have the folio blocked from truncation through other + * means (eg zap_page_range() has it mapped and is holding the page table + * lock). This can also be called from mark_buffer_dirty(), which I + * cannot prove is always protected against truncate. */ void __folio_mark_dirty(struct folio *folio, struct address_space *mapping, int warn) -- 2.33.0
