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From:   Pankaj Raghav <p.raghav@samsung.com>
To:     viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org,
        akpm@linux-foundation.org
Cc:     linux-fsdevel@vger.kernel.org, mcgrof@kernel.org,
        linux-kernel@vger.kernel.org, hare@suse.de, gost.dev@samsung.com,
        Pankaj Raghav <p.raghav@samsung.com>
Subject: [PATCH 1/4] fs/buffer: add folio_set_bh helper
Date:   Mon, 17 Apr 2023 14:36:15 +0200
Message-Id: <20230417123618.22094-2-p.raghav@samsung.com>
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References: <20230417123618.22094-1-p.raghav@samsung.com>
        <CGME20230417123620eucas1p266aa61d2213f94bbe028a98be73b70fc@eucas1p2.samsung.com>
Precedence: bulk

The folio version of set_bh_page(). This is required to convert
create_page_buffers() to folio_create_buffers() later in the series.

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/buffer.c                 | 15 +++++++++++++++
 include/linux/buffer_head.h |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/fs/buffer.c b/fs/buffer.c
index b3eb905f87d6..7e74bd77a81b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1484,6 +1484,21 @@ void set_bh_page(struct buffer_head *bh,
 }
 EXPORT_SYMBOL(set_bh_page);
 
+void folio_set_bh(struct buffer_head *bh, struct folio *folio,
+		  unsigned long offset)
+{
+	bh->b_folio = folio;
+	BUG_ON(offset >= folio_size(folio));
+	if (folio_test_highmem(folio))
+		/*
+		 * This catches illegal uses and preserves the offset:
+		 */
+		bh->b_data = (char *)(0 + offset);
+	else
+		bh->b_data = folio_address(folio) + offset;
+}
+EXPORT_SYMBOL(folio_set_bh);
+
 /*
  * Called when truncating a buffer on a page completely.
  */
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 8f14dca5fed7..7e92d23f4782 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -196,6 +196,8 @@ void mark_buffer_write_io_error(struct buffer_head *bh);
 void touch_buffer(struct buffer_head *bh);
 void set_bh_page(struct buffer_head *bh,
 		struct page *page, unsigned long offset);
+void folio_set_bh(struct buffer_head *bh, struct folio *folio,
+		  unsigned long offset);
 bool try_to_free_buffers(struct folio *);
 struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
 		bool retry);
-- 
2.34.1