The patch titled Subject: mm: return void from folio_start_writeback() and related functions has been added to the -mm mm-unstable branch. Its filename is mm-return-void-from-folio_start_writeback-and-related-functions.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-return-void-from-folio_start_writeback-and-related-functions.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: return void from folio_start_writeback() and related functions Date: Wed, 8 Nov 2023 20:46:05 +0000 Nobody now checks the return value from any of these functions, so add an assertion at the beginning of the function and return void. Link: https://lkml.kernel.org/r/20231108204605.745109-5-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Steve French <sfrench@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page-flags.h | 4 +- mm/folio-compat.c | 4 +- mm/page-writeback.c | 60 ++++++++++++++++------------------- 3 files changed, 32 insertions(+), 36 deletions(-) --- a/include/linux/page-flags.h~mm-return-void-from-folio_start_writeback-and-related-functions +++ a/include/linux/page-flags.h @@ -772,8 +772,8 @@ static __always_inline void SetPageUptod CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) -bool __folio_start_writeback(struct folio *folio, bool keep_write); -bool set_page_writeback(struct page *page); +void __folio_start_writeback(struct folio *folio, bool keep_write); +void set_page_writeback(struct page *page); #define folio_start_writeback(folio) \ __folio_start_writeback(folio, false) --- a/mm/folio-compat.c~mm-return-void-from-folio_start_writeback-and-related-functions +++ a/mm/folio-compat.c @@ -46,9 +46,9 @@ void mark_page_accessed(struct page *pag } EXPORT_SYMBOL(mark_page_accessed); -bool set_page_writeback(struct page *page) +void set_page_writeback(struct page *page) { - return folio_start_writeback(page_folio(page)); + folio_start_writeback(page_folio(page)); } EXPORT_SYMBOL(set_page_writeback); --- a/mm/page-writeback.c~mm-return-void-from-folio_start_writeback-and-related-functions +++ a/mm/page-writeback.c @@ -2982,67 +2982,63 @@ bool __folio_end_writeback(struct folio return ret; } -bool __folio_start_writeback(struct folio *folio, bool keep_write) +void __folio_start_writeback(struct folio *folio, bool keep_write) { long nr = folio_nr_pages(folio); struct address_space *mapping = folio_mapping(folio); - bool ret; int access_ret; + VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); + folio_memcg_lock(folio); if (mapping && mapping_use_writeback_tags(mapping)) { XA_STATE(xas, &mapping->i_pages, folio_index(folio)); struct inode *inode = mapping->host; struct backing_dev_info *bdi = inode_to_bdi(inode); unsigned long flags; + bool on_wblist; xas_lock_irqsave(&xas, flags); xas_load(&xas); - ret = folio_test_set_writeback(folio); - if (!ret) { - bool on_wblist; - - on_wblist = mapping_tagged(mapping, - PAGECACHE_TAG_WRITEBACK); - - xas_set_mark(&xas, PAGECACHE_TAG_WRITEBACK); - if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) { - struct bdi_writeback *wb = inode_to_wb(inode); - - wb_stat_mod(wb, WB_WRITEBACK, nr); - if (!on_wblist) - wb_inode_writeback_start(wb); - } - - /* - * We can come through here when swapping - * anonymous folios, so we don't necessarily - * have an inode to track for sync. - */ - if (mapping->host && !on_wblist) - sb_mark_inode_writeback(mapping->host); + folio_test_set_writeback(folio); + + on_wblist = mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK); + + xas_set_mark(&xas, PAGECACHE_TAG_WRITEBACK); + if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) { + struct bdi_writeback *wb = inode_to_wb(inode); + + wb_stat_mod(wb, WB_WRITEBACK, nr); + if (!on_wblist) + wb_inode_writeback_start(wb); } + + /* + * We can come through here when swapping anonymous + * folios, so we don't necessarily have an inode to + * track for sync. + */ + if (mapping->host && !on_wblist) + sb_mark_inode_writeback(mapping->host); if (!folio_test_dirty(folio)) xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY); if (!keep_write) xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE); xas_unlock_irqrestore(&xas, flags); } else { - ret = folio_test_set_writeback(folio); - } - if (!ret) { - lruvec_stat_mod_folio(folio, NR_WRITEBACK, nr); - zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, nr); + folio_test_set_writeback(folio); } + + lruvec_stat_mod_folio(folio, NR_WRITEBACK, nr); + zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, nr); folio_memcg_unlock(folio); + access_ret = arch_make_folio_accessible(folio); /* * If writeback has been triggered on a page that cannot be made * accessible, it is too late to recover here. */ VM_BUG_ON_FOLIO(access_ret != 0, folio); - - return ret; } EXPORT_SYMBOL(__folio_start_writeback); _ Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are mm-make-mapping_evict_folio-the-preferred-way-to-evict-clean-folios.patch mm-convert-__do_fault-to-use-a-folio.patch mm-use-mapping_evict_folio-in-truncate_error_page.patch mm-convert-soft_offline_in_use_page-to-use-a-folio.patch mm-convert-isolate_page-to-mf_isolate_folio.patch mm-remove-invalidate_inode_page.patch mm-remove-test_set_page_writeback.patch afs-do-not-test-the-return-value-of-folio_start_writeback.patch smb-do-not-test-the-return-value-of-folio_start_writeback.patch mm-return-void-from-folio_start_writeback-and-related-functions.patch