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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-12-20 12:44:51 +0100
committerMatthew Wilcox (Oracle) <willy@infradead.org>2022-01-03 02:28:57 +0100
commita229a4f00d1eab3f665b92dc9f8dbceca9b8f49c (patch)
tree8ec748354a535deaff55631c78366eaaeac0986e /mm/page-writeback.c
parentmm/doc: Add documentation for folio_test_uptodate (diff)
downloadlinux-a229a4f00d1eab3f665b92dc9f8dbceca9b8f49c.tar.xz
linux-a229a4f00d1eab3f665b92dc9f8dbceca9b8f49c.zip
mm/writeback: Improve __folio_mark_dirty() comment
Add some notes about how this function needs to be called. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c6
1 files changed, 5 insertions, 1 deletions
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)