diff mbox series

[04/48] mm/writeback: Improve __folio_mark_dirty() comment

Message ID	20211208042256.1923824-5-willy@infradead.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> From: "Matthew Wilcox (Oracle)" <willy@infradead.org> To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Subject: [PATCH 04/48] mm/writeback: Improve __folio_mark_dirty() comment Date: Wed, 8 Dec 2021 04:22:12 +0000 Message-Id: <20211208042256.1923824-5-willy@infradead.org> In-Reply-To: <20211208042256.1923824-1-willy@infradead.org> References: <20211208042256.1923824-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Folios for 5.17 \| expand [00/48] Folios for 5.17 [01/48] filemap: Remove PageHWPoison check from next_uptodate_page() [02/48] fs/writeback: Convert inode_switch_wbs_work_fn to folios [03/48] mm/doc: Add documentation for folio_test_uptodate [04/48] mm/writeback: Improve __folio_mark_dirty() comment [05/48] pagevec: Add folio_batch [06/48] iov_iter: Add copy_folio_to_iter() [07/48] iov_iter: Convert iter_xarray to use folios [08/48] mm: Add folio_test_pmd_mappable() [09/48] filemap: Add folio_put_wait_locked() [10/48] filemap: Convert page_cache_delete to take a folio [11/48] filemap: Add filemap_unaccount_folio() [12/48] filemap: Convert tracing of page cache operations to folio [13/48] filemap: Add filemap_remove_folio and __filemap_remove_folio [14/48] filemap: Convert find_get_entry to return a folio [15/48] filemap: Remove thp_contains() [16/48] filemap: Convert filemap_get_read_batch to use folios [17/48] filemap: Convert find_get_pages_contig to folios [18/48] filemap: Convert filemap_read_page to take a folio [19/48] filemap: Convert filemap_create_page to folio [20/48] filemap: Convert filemap_range_uptodate to folios [21/48] readahead: Convert page_cache_async_ra() to take a folio [22/48] readahead: Convert page_cache_ra_unbounded to folios [23/48] filemap: Convert do_async_mmap_readahead to take a folio [24/48] filemap: Convert filemap_fault to folio [25/48] filemap: Add read_cache_folio and read_mapping_folio [26/48] filemap: Convert filemap_get_pages to use folios [27/48] filemap: Convert page_cache_delete_batch to folios [28/48] filemap: Use folios in next_uptodate_page [29/48] filemap: Use a folio in filemap_map_pages [30/48] filemap: Use a folio in filemap_page_mkwrite [31/48] filemap: Add filemap_release_folio() [32/48] truncate: Add truncate_cleanup_folio() [33/48] mm: Add unmap_mapping_folio() [34/48] shmem: Convert part of shmem_undo_range() to use a folio [35/48] truncate,shmem: Add truncate_inode_folio() [36/48] truncate: Skip known-truncated indices [37/48] truncate: Convert invalidate_inode_pages2_range() to use a folio [38/48] truncate: Add invalidate_complete_folio2() [39/48] filemap: Convert filemap_read() to use a folio [40/48] filemap: Convert filemap_get_read_batch() to use a folio_batch [41/48] filemap: Return only folios from find_get_entries() [42/48] mm: Convert find_lock_entries() to use a folio_batch [43/48] mm: Remove pagevec_remove_exceptionals() [44/48] fs: Convert vfs_dedupe_file_range_compare to folios [45/48] truncate: Convert invalidate_inode_pages2_range to folios [46/48] truncate,shmem: Handle truncates that split large folios [47/48] XArray: Add xas_advance() [48/48] mm: Use multi-index entries in the page cache

Commit Message

Matthew Wilcox Dec. 8, 2021, 4:22 a.m. UTC

Add some notes about how this function needs to be called.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/page-writeback.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Christoph Hellwig Dec. 23, 2021, 6:52 a.m. UTC | #1

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

diff mbox series

Patch

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)