+ fs-buffer-add-folio_create_empty_buffers-helper.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: fs/buffer: add folio_create_empty_buffers helper
has been added to the -mm mm-unstable branch.  Its filename is
     fs-buffer-add-folio_create_empty_buffers-helper.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fs-buffer-add-folio_create_empty_buffers-helper.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: Pankaj Raghav <p.raghav@samsung.com>
Subject: fs/buffer: add folio_create_empty_buffers helper
Date: Mon, 17 Apr 2023 14:36:17 +0200

Folio version of create_empty_buffers().  This is required to convert
create_page_buffers() to folio_create_buffers() later in the series.

It removes several calls to compound_head() as it works directly on folio
compared to create_empty_buffers().  Hence, create_empty_buffers() has
been modified to call folio_create_empty_buffers().

Link: https://lkml.kernel.org/r/20230417123618.22094-4-p.raghav@samsung.com
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/buffer.c                 |   28 +++++++++++++++++-----------
 include/linux/buffer_head.h |    2 ++
 2 files changed, 19 insertions(+), 11 deletions(-)

--- a/fs/buffer.c~fs-buffer-add-folio_create_empty_buffers-helper
+++ a/fs/buffer.c
@@ -1594,18 +1594,17 @@ out:
 }
 EXPORT_SYMBOL(block_invalidate_folio);
 
-
 /*
  * We attach and possibly dirty the buffers atomically wrt
  * block_dirty_folio() via private_lock.  try_to_free_buffers
- * is already excluded via the page lock.
+ * is already excluded via the folio lock.
  */
-void create_empty_buffers(struct page *page,
-			unsigned long blocksize, unsigned long b_state)
+void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize,
+				unsigned long b_state)
 {
 	struct buffer_head *bh, *head, *tail;
 
-	head = alloc_page_buffers(page, blocksize, true);
+	head = folio_alloc_buffers(folio, blocksize, true);
 	bh = head;
 	do {
 		bh->b_state |= b_state;
@@ -1614,19 +1613,26 @@ void create_empty_buffers(struct page *p
 	} while (bh);
 	tail->b_this_page = head;
 
-	spin_lock(&page->mapping->private_lock);
-	if (PageUptodate(page) || PageDirty(page)) {
+	spin_lock(&folio->mapping->private_lock);
+	if (folio_test_uptodate(folio) || folio_test_dirty(folio)) {
 		bh = head;
 		do {
-			if (PageDirty(page))
+			if (folio_test_dirty(folio))
 				set_buffer_dirty(bh);
-			if (PageUptodate(page))
+			if (folio_test_uptodate(folio))
 				set_buffer_uptodate(bh);
 			bh = bh->b_this_page;
 		} while (bh != head);
 	}
-	attach_page_private(page, head);
-	spin_unlock(&page->mapping->private_lock);
+	folio_attach_private(folio, head);
+	spin_unlock(&folio->mapping->private_lock);
+}
+EXPORT_SYMBOL(folio_create_empty_buffers);
+
+void create_empty_buffers(struct page *page,
+			unsigned long blocksize, unsigned long b_state)
+{
+	folio_create_empty_buffers(page_folio(page), blocksize, b_state);
 }
 EXPORT_SYMBOL(create_empty_buffers);
 
--- a/include/linux/buffer_head.h~fs-buffer-add-folio_create_empty_buffers-helper
+++ a/include/linux/buffer_head.h
@@ -205,6 +205,8 @@ 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);
 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 p.raghav@samsung.com are

orangefs-use-folios-in-orangefs_readahead.patch
mpage-split-submit_bio-and-bio-end_io-handler-for-reads-and-writes.patch
mpage-use-folios-in-bio-end_io-handler.patch
fs-buffer-add-folio_set_bh-helper.patch
buffer-add-folio_alloc_buffers-helper.patch
fs-buffer-add-folio_create_empty_buffers-helper.patch
fs-buffer-convert-create_page_buffers-to-folio_create_buffers.patch