Commit d685c668 authored Dec 15, 2022 by Matthew Wilcox (Oracle) Committed by Andrew Morton Jan 18, 2023

buffer: add b_folio as an alias of b_page

Patch series "Start converting buffer_heads to use folios".

I was hoping that filesystems would convert from buffer_heads to iomap,
but that's not happening particularly quickly.  So the buffer_head
infrastructure needs to be converted from being page-based to being
folio-based.


This patch (of 12):

Buffer heads point to the allocation (ie the folio), not the page.  This
is currently the same thing for all filesystems that use buffer heads, so
this is a safe transitional step.

Link: https://lkml.kernel.org/r/20221215214402.3522366-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20221215214402.3522366-2-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 9c67a207

include/linux/buffer_head.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -61,7 +61,10 @@ typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
		struct buffer_head {
		unsigned long b_state; /* buffer state bitmap (see above) */
		struct buffer_head b_this_page;/ circular list of page's buffers */
		union {
		struct page b_page; / the page this bh is mapped to */
		struct folio b_folio; / the folio this bh is mapped to */
		};

		sector_t b_blocknr; /* start block number */
		size_t b_size; /* size of mapping */