The patch titled
Subject: buffer: add b_folio as an alias of b_page
has been added to the -mm mm-unstable branch. Its filename is
buffer-add-b_folio-as-an-alias-of-b_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-add-b_folio-as-an-alias-of-b_page.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: add b_folio as an alias of b_page
Date: Thu, 15 Dec 2022 21:43:51 +0000
Patch series "Start converting buffer_heads to use folios".
I was hoping that filesystems would convert from buffer_heads to iomap,
but that's not happening particularly quickly. So the buffer_head
infrastructure needs to be converted from being page-based to being
folio-based.
This patch (of 12):
Buffer heads point to the allocation (ie the folio), not the page. This
is currently the same thing for all filesystems that use buffer heads, so
this is a safe transitional step.
Link: https://lkml.kernel.org/r/20221215214402.3522366-1-willy@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20221215214402.3522366-2-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/buffer_head.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/include/linux/buffer_head.h~buffer-add-b_folio-as-an-alias-of-b_page
+++ a/include/linux/buffer_head.h
@@ -61,7 +61,10 @@ typedef void (bh_end_io_t)(struct buffer
struct buffer_head {
unsigned long b_state; /* buffer state bitmap (see above) */
struct buffer_head *b_this_page;/* circular list of page's buffers */
- struct page *b_page; /* the page this bh is mapped to */
+ union {
+ struct page *b_page; /* the page this bh is mapped to */
+ struct folio *b_folio; /* the folio this bh is mapped to */
+ };
sector_t b_blocknr; /* start block number */
size_t b_size; /* size of mapping */
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
buffer-add-b_folio-as-an-alias-of-b_page.patch
buffer-replace-obvious-uses-of-b_page-with-b_folio.patch
buffer-use-b_folio-in-touch_buffer.patch
buffer-use-b_folio-in-end_buffer_async_read.patch
buffer-use-b_folio-in-end_buffer_async_write.patch
page_io-remove-buffer_head-include.patch
buffer-use-b_folio-in-mark_buffer_dirty.patch
gfs2-replace-obvious-uses-of-b_page-with-b_folio.patch
jbd2-replace-obvious-uses-of-b_page-with-b_folio.patch
nilfs2-replace-obvious-uses-of-b_page-with-b_folio.patch
reiserfs-replace-obvious-uses-of-b_page-with-b_folio.patch
mpage-use-b_folio-in-do_mpage_readpage.patch
