The patch titled
Subject: buffer: make folio_create_empty_buffers() return a buffer_head
has been added to the -mm mm-unstable branch. Its filename is
buffer-make-folio_create_empty_buffers-return-a-buffer_head.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-make-folio_create_empty_buffers-return-a-buffer_head.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: buffer: make folio_create_empty_buffers() return a buffer_head
Date: Mon, 16 Oct 2023 21:10:49 +0100
Almost all callers want to know the first BH that was allocated for this
folio. We already have that handy, so return it.
Link: https://lkml.kernel.org/r/20231016201114.1928083-3-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Cc: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/buffer.c | 24 +++++++++++++-----------
include/linux/buffer_head.h | 4 ++--
2 files changed, 15 insertions(+), 13 deletions(-)
--- a/fs/buffer.c~buffer-make-folio_create_empty_buffers-return-a-buffer_head
+++ a/fs/buffer.c
@@ -1646,8 +1646,8 @@ EXPORT_SYMBOL(block_invalidate_folio);
* block_dirty_folio() via private_lock. try_to_free_buffers
* is already excluded via the folio lock.
*/
-void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize,
- unsigned long b_state)
+struct buffer_head *folio_create_empty_buffers(struct folio *folio,
+ unsigned long blocksize, unsigned long b_state)
{
struct buffer_head *bh, *head, *tail;
gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT | __GFP_NOFAIL;
@@ -1674,6 +1674,8 @@ void folio_create_empty_buffers(struct f
}
folio_attach_private(folio, head);
spin_unlock(&folio->mapping->private_lock);
+
+ return head;
}
EXPORT_SYMBOL(folio_create_empty_buffers);
@@ -1775,13 +1777,15 @@ static struct buffer_head *folio_create_
struct inode *inode,
unsigned int b_state)
{
+ struct buffer_head *bh;
+
BUG_ON(!folio_test_locked(folio));
- if (!folio_buffers(folio))
- folio_create_empty_buffers(folio,
- 1 << READ_ONCE(inode->i_blkbits),
- b_state);
- return folio_buffers(folio);
+ bh = folio_buffers(folio);
+ if (!bh)
+ bh = folio_create_empty_buffers(folio,
+ 1 << READ_ONCE(inode->i_blkbits), b_state);
+ return bh;
}
/*
@@ -2681,10 +2685,8 @@ int block_truncate_page(struct address_s
return PTR_ERR(folio);
bh = folio_buffers(folio);
- if (!bh) {
- folio_create_empty_buffers(folio, blocksize, 0);
- bh = folio_buffers(folio);
- }
+ if (!bh)
+ bh = folio_create_empty_buffers(folio, blocksize, 0);
/* Find the buffer that contains "offset" */
offset = offset_in_folio(folio, from);
--- a/include/linux/buffer_head.h~buffer-make-folio_create_empty_buffers-return-a-buffer_head
+++ a/include/linux/buffer_head.h
@@ -203,8 +203,8 @@ struct buffer_head *alloc_page_buffers(s
bool retry);
void create_empty_buffers(struct page *, unsigned long,
unsigned long b_state);
-void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize,
- unsigned long b_state);
+struct buffer_head *folio_create_empty_buffers(struct folio *folio,
+ unsigned long blocksize, unsigned long b_state);
void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
void end_buffer_async_write(struct buffer_head *bh, int uptodate);
_
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
filemap-remove-use-of-wait-bookmarks.patch
sched-remove-wait-bookmarks.patch
buffer-return-bool-from-grow_dev_folio.patch
buffer-make-folio_create_empty_buffers-return-a-buffer_head.patch
mpage-convert-map_buffer_to_folio-to-folio_create_empty_buffers.patch
ext4-convert-to-folio_create_empty_buffers.patch
buffer-add-get_nth_bh.patch
gfs2-convert-inode-unstuffing-to-use-a-folio.patch
gfs2-convert-gfs2_getbuf-to-folios.patch
gfs2-convert-gfs2_getjdatabuf-to-use-a-folio.patch
gfs2-convert-gfs2_write_buf_to_page-to-use-a-folio.patch
nilfs2-convert-nilfs_mdt_freeze_buffer-to-use-a-folio.patch
nilfs2-convert-nilfs_grab_buffer-to-use-a-folio.patch
nilfs2-convert-nilfs_copy_page-to-nilfs_copy_folio.patch
nilfs2-convert-nilfs_mdt_forget_block-to-use-a-folio.patch
nilfs2-convert-nilfs_mdt_get_frozen_buffer-to-use-a-folio.patch
nilfs2-remove-nilfs_page_get_nth_block.patch
nilfs2-convert-nilfs_lookup_dirty_data_buffers-to-use-folio_create_empty_buffers.patch
ntfs-convert-ntfs_read_block-to-use-a-folio.patch
ntfs-convert-ntfs_writepage-to-use-a-folio.patch
ntfs-convert-ntfs_prepare_pages_for_non_resident_write-to-folios.patch
ntfs3-convert-ntfs_zero_range-to-use-a-folio.patch
ocfs2-convert-ocfs2_map_page_blocks-to-use-a-folio.patch
reiserfs-convert-writepage-to-use-a-folio.patch
ufs-add-ufs_get_locked_folio-and-ufs_put_locked_folio.patch
ufs-use-ufs_get_locked_folio-in-ufs_alloc_lastblock.patch
ufs-convert-ufs_change_blocknr-to-use-folios.patch
ufs-remove-ufs_get_locked_page.patch
buffer-remove-folio_create_empty_buffers.patch
