[merged mm-stable] buffer-add-get_nth_bh.patch removed from -mm tree

[merged mm-stable] buffer-add-get_nth_bh.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: buffer: add get_nth_bh()
has been removed from the -mm tree.  Its filename was
     buffer-add-get_nth_bh.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: buffer: add get_nth_bh()
Date: Mon, 16 Oct 2023 21:10:52 +0100

Extract this useful helper from nilfs_page_get_nth_block()

Link: https://lkml.kernel.org/r/20231016201114.1928083-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/nilfs2/page.h            |    7 +------
 include/linux/buffer_head.h |   22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

--- a/fs/nilfs2/page.h~buffer-add-get_nth_bh
+++ a/fs/nilfs2/page.h
@@ -55,12 +55,7 @@ unsigned long nilfs_find_uncommitted_ext
 static inline struct buffer_head *
 nilfs_page_get_nth_block(struct page *page, unsigned int count)
 {
-	struct buffer_head *bh = page_buffers(page);
-
-	while (count-- > 0)
-		bh = bh->b_this_page;
-	get_bh(bh);
-	return bh;
+	return get_nth_bh(page_buffers(page), count);
 }
 
 #endif /* _NILFS_PAGE_H */
--- a/include/linux/buffer_head.h~buffer-add-get_nth_bh
+++ a/include/linux/buffer_head.h
@@ -457,6 +457,28 @@ __bread(struct block_device *bdev, secto
 	return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
 }
 
+/**
+ * get_nth_bh - Get a reference on the n'th buffer after this one.
+ * @bh: The buffer to start counting from.
+ * @count: How many buffers to skip.
+ *
+ * This is primarily useful for finding the nth buffer in a folio; in
+ * that case you pass the head buffer and the byte offset in the folio
+ * divided by the block size.  It can be used for other purposes, but
+ * it will wrap at the end of the folio rather than returning NULL or
+ * proceeding to the next folio for you.
+ *
+ * Return: The requested buffer with an elevated refcount.
+ */
+static inline __must_check
+struct buffer_head *get_nth_bh(struct buffer_head *bh, unsigned int count)
+{
+	while (count--)
+		bh = bh->b_this_page;
+	get_bh(bh);
+	return bh;
+}
+
 bool block_dirty_folio(struct address_space *mapping, struct folio *folio);
 
 #ifdef CONFIG_BUFFER_HEAD
_

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