From 465e5e6a1698f3325f5d2262d2875779b06b50c7 Mon Sep 17 00:00:00 2001
From: Pankaj Raghav <p.raghav@samsung.com>
Date: Mon, 17 Apr 2023 14:36:15 +0200
Subject: [PATCH] fs/buffer: add folio_set_bh helper
Patch series "convert create_page_buffers to folio_create_buffers".
One of the first kernel panic we hit when we try to increase the block
size > 4k is inside create_page_buffers()[1]. Even though buffer.c
function do not support large folios (folios > PAGE_SIZE) at the moment,
these changes are required when we want to remove that constraint.
This patch (of 4):
The folio version of set_bh_page(). This is required to convert
create_page_buffers() to folio_create_buffers() later in the series.
Link: https://lkml.kernel.org/r/20230417123618.22094-1-p.raghav@samsung.com
Link: https://lkml.kernel.org/r/20230417123618.22094-2-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 | 15 +++++++++++++++
include/linux/buffer_head.h | 2 ++
2 files changed, 17 insertions(+)
diff --git a/fs/buffer.c b/fs/buffer.c
index 9e1e2add541e0..009d950fbf426 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1485,6 +1485,21 @@ 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 8f14dca5fed75..7e92d23f4782e 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);
--
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