+ writeback-remove-a-use-of-write_cache_pages-from-do_writepages.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: writeback: remove a use of write_cache_pages() from do_writepages()
has been added to the -mm mm-unstable branch.  Its filename is
     writeback-remove-a-use-of-write_cache_pages-from-do_writepages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/writeback-remove-a-use-of-write_cache_pages-from-do_writepages.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: writeback: remove a use of write_cache_pages() from do_writepages()
Date: Thu, 15 Feb 2024 07:36:49 +0100

Use the new writeback_iter() directly instead of indirecting through a
callback.

[hch@lst.de: ported to the while based iter style]
Link: https://lkml.kernel.org/r/20240215063649.2164017-15-hch@lst.de
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page-writeback.c |   31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

--- a/mm/page-writeback.c~writeback-remove-a-use-of-write_cache_pages-from-do_writepages
+++ a/mm/page-writeback.c
@@ -2577,15 +2577,25 @@ int write_cache_pages(struct address_spa
 }
 EXPORT_SYMBOL(write_cache_pages);
 
-static int writepage_cb(struct folio *folio, struct writeback_control *wbc,
-		void *data)
+static int writeback_use_writepage(struct address_space *mapping,
+		struct writeback_control *wbc)
 {
-	struct address_space *mapping = data;
-	int ret = mapping->a_ops->writepage(&folio->page, wbc);
+	struct folio *folio = NULL;
+	struct blk_plug plug;
+	int err;
 
-	if (ret < 0)
-		mapping_set_error(mapping, ret);
-	return ret;
+	blk_start_plug(&plug);
+	while ((folio = writeback_iter(mapping, wbc, folio, &err))) {
+		err = mapping->a_ops->writepage(&folio->page, wbc);
+		if (err == AOP_WRITEPAGE_ACTIVATE) {
+			folio_unlock(folio);
+			err = 0;
+		}
+		mapping_set_error(mapping, err);
+	}
+	blk_finish_plug(&plug);
+
+	return err;
 }
 
 int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
@@ -2601,12 +2611,7 @@ int do_writepages(struct address_space *
 		if (mapping->a_ops->writepages) {
 			ret = mapping->a_ops->writepages(mapping, wbc);
 		} else if (mapping->a_ops->writepage) {
-			struct blk_plug plug;
-
-			blk_start_plug(&plug);
-			ret = write_cache_pages(mapping, wbc, writepage_cb,
-						mapping);
-			blk_finish_plug(&plug);
+			ret = writeback_use_writepage(mapping, wbc);
 		} else {
 			/* deal with chardevs and other special files */
 			ret = 0;
_

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

memcg-convert-mem_cgroup_move_charge_pte_range-to-use-a-folio.patch
memcg-return-the-folio-in-union-mc_target.patch
memcg-use-a-folio-in-get_mctgt_type.patch
memcg-use-a-folio-in-get_mctgt_type_thp.patch
mm-add-pfn_swap_entry_folio.patch
proc-use-pfn_swap_entry_folio-where-obvious.patch
mprotect-use-pfn_swap_entry_folio.patch
highmem-add-kernel-doc-for-memcpy__folio.patch
rmap-replace-two-calls-to-compound_order-with-folio_order.patch
writeback-remove-a-duplicate-prototype-for-tag_pages_for_writeback.patch
writeback-factor-folio_prepare_writeback-out-of-write_cache_pages.patch
writeback-factor-writeback_get_batch-out-of-write_cache_pages.patch
writeback-simplify-the-loops-in-write_cache_pages.patch
pagevec-add-ability-to-iterate-a-queue.patch
writeback-use-the-folio_batch-queue-iterator.patch
writeback-move-the-folio_prepare_writeback-loop-out-of-write_cache_pages.patch
writeback-remove-a-use-of-write_cache_pages-from-do_writepages.patch
bounds-support-non-power-of-two-config_nr_cpus.patch