[PATCH 1/3] bcachefs: Convert to readahead

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Use the new readahead method instead of readpages.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/bcachefs/fs-io.c | 29 +++++++++++------------------
 fs/bcachefs/fs-io.h |  3 +--
 fs/bcachefs/fs.c    |  2 +-
 3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index 3aed2ca4dced..d390cbb82233 100644
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -663,26 +663,22 @@ struct readpages_iter {
 };
 
 static int readpages_iter_init(struct readpages_iter *iter,
-			       struct address_space *mapping,
-			       struct list_head *pages, unsigned nr_pages)
+			       struct readahead_control *ractl)
 {
+	unsigned i, nr_pages = readahead_count(ractl);
+
 	memset(iter, 0, sizeof(*iter));
 
-	iter->mapping	= mapping;
-	iter->offset	= list_last_entry(pages, struct page, lru)->index;
+	iter->mapping	= ractl->mapping;
+	iter->offset	= readahead_index(ractl);
 
 	iter->pages = kmalloc_array(nr_pages, sizeof(struct page *), GFP_NOFS);
 	if (!iter->pages)
 		return -ENOMEM;
 
-	while (!list_empty(pages)) {
-		struct page *page = list_last_entry(pages, struct page, lru);
-
-		__bch2_page_state_create(page, __GFP_NOFAIL);
-
-		iter->pages[iter->nr_pages++] = page;
-		list_del(&page->lru);
-	}
+	__readahead_batch(ractl, iter->pages, nr_pages);
+	for (i = 0; i < nr_pages; i++)
+		__bch2_page_state_create(iter->pages[i], __GFP_NOFAIL);
 
 	return 0;
 }
@@ -889,10 +885,9 @@ static void bchfs_read(struct btree_trans *trans, struct btree_iter *iter,
 	bkey_on_stack_exit(&sk, c);
 }
 
-int bch2_readpages(struct file *file, struct address_space *mapping,
-		   struct list_head *pages, unsigned nr_pages)
+void bch2_readahead(struct readahead_control *ractl)
 {
-	struct bch_inode_info *inode = to_bch_ei(mapping->host);
+	struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct bch_io_opts opts = io_opts(c, &inode->ei_inode);
 	struct btree_trans trans;
@@ -901,7 +896,7 @@ int bch2_readpages(struct file *file, struct address_space *mapping,
 	struct readpages_iter readpages_iter;
 	int ret;
 
-	ret = readpages_iter_init(&readpages_iter, mapping, pages, nr_pages);
+	ret = readpages_iter_init(&readpages_iter, ractl);
 	BUG_ON(ret);
 
 	bch2_trans_init(&trans, c, 0, 0);
@@ -936,8 +931,6 @@ int bch2_readpages(struct file *file, struct address_space *mapping,
 
 	bch2_trans_exit(&trans);
 	kfree(readpages_iter.pages);
-
-	return 0;
 }
 
 static void __bchfs_readpage(struct bch_fs *c, struct bch_read_bio *rbio,
diff --git a/fs/bcachefs/fs-io.h b/fs/bcachefs/fs-io.h
index 7063556d289b..2537a3d25ede 100644
--- a/fs/bcachefs/fs-io.h
+++ b/fs/bcachefs/fs-io.h
@@ -19,8 +19,7 @@ int bch2_writepage(struct page *, struct writeback_control *);
 int bch2_readpage(struct file *, struct page *);
 
 int bch2_writepages(struct address_space *, struct writeback_control *);
-int bch2_readpages(struct file *, struct address_space *,
-		   struct list_head *, unsigned);
+void bch2_readahead(struct readahead_control *);
 
 int bch2_write_begin(struct file *, struct address_space *, loff_t,
 		     unsigned, unsigned, struct page **, void **);
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 267d31135269..cecdb956096a 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1064,7 +1064,7 @@ static const struct address_space_operations bch_address_space_operations = {
 	.writepage	= bch2_writepage,
 	.readpage	= bch2_readpage,
 	.writepages	= bch2_writepages,
-	.readpages	= bch2_readpages,
+	.readahead	= bch2_readahead,
 	.set_page_dirty	= __set_page_dirty_nobuffers,
 	.write_begin	= bch2_write_begin,
 	.write_end	= bch2_write_end,
-- 
2.28.0