fs: remove clean_page_buffers()

Patch series "Clean up the writeback paths".

Most of these patches verge on the trivial, converting filesystems that
just use block_write_full_page() to use mpage_writepages().  But as we saw
with Christoph's earlier patchset, there can be some "interesting"
gotchas, and I clearly haven't tested the majority of filesystems I've
touched here.

Patches 3 & 4 get rid of a lot of stack usage on architectures with larger
page sizes; 1024 bytes on 64-bit systems with 64KiB pages.  It starts to
open the door to larger folio sizes on all architectures, but it's
certainly not enough yet.

Patch 14 is kind of trivial, but it's nice to get that simplification in.


This patch (of 14):

This function has been unused since the removal of bdev_write_page().

Link: https://lkml.kernel.org/r/20231215200245.748418-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231215200245.748418-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/mpage.c

@@ -455,16 +455,6 @@ static void clean_buffers(struct page *page, unsigned first_unmapped)
 		try_to_free_buffers(page_folio(page));
 }
 
-/*
- * For situations where we want to clean all buffers attached to a page.
- * We don't need to calculate how many buffers are attached to the page,
- * we just need to specify a number larger than the maximum number of buffers.
- */
-void clean_page_buffers(struct page *page)
-{
-	clean_buffers(page, ~0U);
-}
-
 static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 		      void *data)
 {

include/linux/buffer_head.h

@@ -270,7 +270,6 @@ int generic_write_end(struct file *, struct address_space *,
 				loff_t, unsigned, unsigned,
 				struct page *, void *);
 void folio_zero_new_buffers(struct folio *folio, size_t from, size_t to);
-void clean_page_buffers(struct page *page);
 int cont_write_begin(struct file *, struct address_space *, loff_t,
 			unsigned, struct page **, void **,
 			get_block_t *, loff_t *);