The patch titled
Subject: mm: make __end_folio_writeback() return void
has been added to the -mm mm-unstable branch. Its filename is
mm-make-__end_folio_writeback-return-void.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-make-__end_folio_writeback-return-void.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: make __end_folio_writeback() return void
Date: Wed, 4 Oct 2023 17:53:16 +0100
Rather than check the result of test-and-clear, just check that we have
the writeback bit set at the start. This wouldn't catch every case, but
it's good enough (and enables the next patch).
Link: https://lkml.kernel.org/r/20231004165317.1061855-17-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Richard Henderson <richard.henderson@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 9 +++++++--
mm/internal.h | 2 +-
mm/page-writeback.c | 38 ++++++++++++++++----------------------
3 files changed, 24 insertions(+), 25 deletions(-)
--- a/mm/filemap.c~mm-make-__end_folio_writeback-return-void
+++ a/mm/filemap.c
@@ -1593,9 +1593,15 @@ EXPORT_SYMBOL(folio_wait_private_2_killa
/**
* folio_end_writeback - End writeback against a folio.
* @folio: The folio.
+ *
+ * The folio must actually be under writeback.
+ *
+ * Context: May be called from process or interrupt context.
*/
void folio_end_writeback(struct folio *folio)
{
+ VM_BUG_ON_FOLIO(!folio_test_writeback(folio), folio);
+
/*
* folio_test_clear_reclaim() could be used here but it is an
* atomic operation and overkill in this particular case. Failing
@@ -1615,8 +1621,7 @@ void folio_end_writeback(struct folio *f
* reused before the folio_wake().
*/
folio_get(folio);
- if (!__folio_end_writeback(folio))
- BUG();
+ __folio_end_writeback(folio);
smp_mb__after_atomic();
folio_wake(folio, PG_writeback);
--- a/mm/internal.h~mm-make-__end_folio_writeback-return-void
+++ a/mm/internal.h
@@ -105,7 +105,7 @@ static inline void wake_throttle_isolate
vm_fault_t do_swap_page(struct vm_fault *vmf);
void folio_rotate_reclaimable(struct folio *folio);
-bool __folio_end_writeback(struct folio *folio);
+void __folio_end_writeback(struct folio *folio);
void deactivate_file_folio(struct folio *folio);
void folio_activate(struct folio *folio);
--- a/mm/page-writeback.c~mm-make-__end_folio_writeback-return-void
+++ a/mm/page-writeback.c
@@ -2940,11 +2940,10 @@ static void wb_inode_writeback_end(struc
spin_unlock_irqrestore(&wb->work_lock, flags);
}
-bool __folio_end_writeback(struct folio *folio)
+void __folio_end_writeback(struct folio *folio)
{
long nr = folio_nr_pages(folio);
struct address_space *mapping = folio_mapping(folio);
- bool ret;
folio_memcg_lock(folio);
if (mapping && mapping_use_writeback_tags(mapping)) {
@@ -2953,19 +2952,16 @@ bool __folio_end_writeback(struct folio
unsigned long flags;
xa_lock_irqsave(&mapping->i_pages, flags);
- ret = folio_test_clear_writeback(folio);
- if (ret) {
- __xa_clear_mark(&mapping->i_pages, folio_index(folio),
- 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);
- __wb_writeout_add(wb, nr);
- if (!mapping_tagged(mapping,
- PAGECACHE_TAG_WRITEBACK))
- wb_inode_writeback_end(wb);
- }
+ folio_test_clear_writeback(folio);
+ __xa_clear_mark(&mapping->i_pages, folio_index(folio),
+ 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);
+ __wb_writeout_add(wb, nr);
+ if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
+ wb_inode_writeback_end(wb);
}
if (mapping->host && !mapping_tagged(mapping,
@@ -2974,15 +2970,13 @@ bool __folio_end_writeback(struct folio
xa_unlock_irqrestore(&mapping->i_pages, flags);
} else {
- ret = folio_test_clear_writeback(folio);
- }
- if (ret) {
- lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr);
- zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr);
- node_stat_mod_folio(folio, NR_WRITTEN, nr);
+ folio_test_clear_writeback(folio);
}
+
+ lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr);
+ zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr);
+ node_stat_mod_folio(folio, NR_WRITTEN, nr);
folio_memcg_unlock(folio);
- return ret;
}
bool __folio_start_writeback(struct folio *folio, bool keep_write)
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-make-lock_folio_maybe_drop_mmap-vma-lock-aware.patch
mm-call-wp_page_copy-under-the-vma-lock.patch
mm-handle-shared-faults-under-the-vma-lock.patch
mm-handle-cow-faults-under-the-vma-lock.patch
mm-handle-read-faults-under-the-vma-lock.patch
mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
iomap-hold-state_lock-over-call-to-ifs_set_range_uptodate.patch
iomap-protect-read_bytes_pending-with-the-state_lock.patch
mm-add-folio_end_read.patch
ext4-use-folio_end_read.patch
buffer-use-folio_end_read.patch
iomap-use-folio_end_read.patch
bitops-add-xor_unlock_is_negative_byte.patch
alpha-implement-xor_unlock_is_negative_byte.patch
m68k-implement-xor_unlock_is_negative_byte.patch
mips-implement-xor_unlock_is_negative_byte.patch
powerpc-implement-arch_xor_unlock_is_negative_byte-on-32-bit.patch
riscv-implement-xor_unlock_is_negative_byte.patch
s390-implement-arch_xor_unlock_is_negative_byte.patch
mm-delete-checks-for-xor_unlock_is_negative_byte.patch
mm-add-folio_xor_flags_has_waiters.patch
mm-make-__end_folio_writeback-return-void.patch
mm-use-folio_xor_flags_has_waiters-in-folio_end_writeback.patch
