+ buffer-use-a-folio-in-__find_get_block_slow.patch added to mm-unstable branch

+ buffer-use-a-folio-in-__find_get_block_slow.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: buffer: use a folio in __find_get_block_slow()
has been added to the -mm mm-unstable branch.  Its filename is
     buffer-use-a-folio-in-__find_get_block_slow.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-use-a-folio-in-__find_get_block_slow.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@infradead.org>
Subject: buffer: use a folio in __find_get_block_slow()
Date: Mon, 12 Jun 2023 22:01:40 +0100

Saves a call to compound_head() and may be needed to support block size >
PAGE_SIZE.

Link: https://lkml.kernel.org/r/20230612210141.730128-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/buffer.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/fs/buffer.c~buffer-use-a-folio-in-__find_get_block_slow
+++ a/fs/buffer.c
@@ -195,19 +195,19 @@ __find_get_block_slow(struct block_devic
 	pgoff_t index;
 	struct buffer_head *bh;
 	struct buffer_head *head;
-	struct page *page;
+	struct folio *folio;
 	int all_mapped = 1;
 	static DEFINE_RATELIMIT_STATE(last_warned, HZ, 1);
 
 	index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);
-	page = find_get_page_flags(bd_mapping, index, FGP_ACCESSED);
-	if (!page)
+	folio = __filemap_get_folio(bd_mapping, index, FGP_ACCESSED, 0);
+	if (IS_ERR(folio))
 		goto out;
 
 	spin_lock(&bd_mapping->private_lock);
-	if (!page_has_buffers(page))
+	head = folio_buffers(folio);
+	if (!head)
 		goto out_unlock;
-	head = page_buffers(page);
 	bh = head;
 	do {
 		if (!buffer_mapped(bh))
@@ -237,7 +237,7 @@ __find_get_block_slow(struct block_devic
 	}
 out_unlock:
 	spin_unlock(&bd_mapping->private_lock);
-	put_page(page);
+	folio_put(folio);
 out:
 	return ret;
 }
_

Patches currently in -mm which might be from willy@infradead.org are

gfs2-use-a-folio-inside-gfs2_jdata_writepage.patch
gfs2-pass-a-folio-to-__gfs2_jdata_write_folio.patch
gfs2-convert-gfs2_write_jdata_page-to-gfs2_write_jdata_folio.patch
buffer-convert-__block_write_full_page-to-__block_write_full_folio.patch
gfs2-support-ludicrously-large-folios-in-gfs2_trans_add_databufs.patch
buffer-make-block_write_full_page-handle-large-folios-correctly.patch
buffer-convert-block_page_mkwrite-to-use-a-folio.patch
buffer-convert-__block_commit_write-to-take-a-folio.patch
buffer-convert-page_zero_new_buffers-to-folio_zero_new_buffers.patch
buffer-convert-grow_dev_page-to-use-a-folio.patch
buffer-convert-init_page_buffers-to-folio_init_buffers.patch
buffer-convert-link_dev_buffers-to-take-a-folio.patch
buffer-use-a-folio-in-__find_get_block_slow.patch
buffer-convert-block_truncate_page-to-use-a-folio.patch