| Message ID | 20250226153614.3774896-1-willy@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Assert the folio is locked in folio_start_writeback() | expand |
On Wed, Feb 26, 2025 at 03:36:12PM +0000, Matthew Wilcox (Oracle) wrote: > The folio must be locked when we start writeback in order to > prevent writeback from being started twice on the same folio. > I don't expect this to catch any problems, but it should be > good documentation. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> LGTM Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> --D > --- > mm/page-writeback.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index eb55ece39c56..8b325aa525eb 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -3109,6 +3109,7 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > int access_ret; > > VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); > + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); > > if (mapping && mapping_use_writeback_tags(mapping)) { > XA_STATE(xas, &mapping->i_pages, folio_index(folio)); > -- > 2.47.2 > >
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index eb55ece39c56..8b325aa525eb 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -3109,6 +3109,7 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) int access_ret; VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); if (mapping && mapping_use_writeback_tags(mapping)) { XA_STATE(xas, &mapping->i_pages, folio_index(folio));
The folio must be locked when we start writeback in order to prevent writeback from being started twice on the same folio. I don't expect this to catch any problems, but it should be good documentation. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- mm/page-writeback.c | 1 + 1 file changed, 1 insertion(+)