f2fs: convert from readpages to readahead

Use the new readahead operation in f2fs
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-23-willy@infradead.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/f2fs/data.c

@@ -2178,8 +2178,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
  * from read-ahead.
  */
 static int f2fs_mpage_readpages(struct address_space *mapping,
-			struct list_head *pages, struct page *page,
-			unsigned nr_pages, bool is_readahead)
+		struct readahead_control *rac, struct page *page)
 {
 	struct bio *bio = NULL;
 	sector_t last_block_in_bio = 0;
@@ -2197,6 +2196,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 		.nr_cpages = 0,
 	};
 #endif
+	unsigned nr_pages = rac ? readahead_count(rac) : 1;
 	unsigned max_nr_pages = nr_pages;
 	int ret = 0;
 
@@ -2210,15 +2210,9 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 	map.m_may_create = false;
 
 	for (; nr_pages; nr_pages--) {
-		if (pages) {
-			page = list_last_entry(pages, struct page, lru);
-
+		if (rac) {
+			page = readahead_page(rac);
 			prefetchw(&page->flags);
-			list_del(&page->lru);
-			if (add_to_page_cache_lru(page, mapping,
-						  page_index(page),
-						  readahead_gfp_mask(mapping)))
-				goto next_page;
 		}
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
@@ -2228,7 +2222,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 				ret = f2fs_read_multi_pages(&cc, &bio,
 							max_nr_pages,
 							&last_block_in_bio,
-							is_readahead, false);
+							rac != NULL, false);
 				f2fs_destroy_compress_ctx(&cc);
 				if (ret)
 					goto set_error_page;
@@ -2251,7 +2245,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 #endif
 
 		ret = f2fs_read_single_page(inode, page, max_nr_pages, &map,
-					&bio, &last_block_in_bio, is_readahead);
+					&bio, &last_block_in_bio, rac);
 		if (ret) {
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 set_error_page:
@@ -2260,8 +2254,10 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 			zero_user_segment(page, 0, PAGE_SIZE);
 			unlock_page(page);
 		}
+#ifdef CONFIG_F2FS_FS_COMPRESSION
 next_page:
-		if (pages)
+#endif
+		if (rac)
 			put_page(page);
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION
@@ -2271,16 +2267,15 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 				ret = f2fs_read_multi_pages(&cc, &bio,
 							max_nr_pages,
 							&last_block_in_bio,
-							is_readahead, false);
+							rac != NULL, false);
 				f2fs_destroy_compress_ctx(&cc);
 			}
 		}
 #endif
 	}
-	BUG_ON(pages && !list_empty(pages));
 	if (bio)
 		__submit_bio(F2FS_I_SB(inode), bio, DATA);
-	return pages ? 0 : ret;
+	return ret;
 }
 
 static int f2fs_read_data_page(struct file *file, struct page *page)
@@ -2299,28 +2294,24 @@ static int f2fs_read_data_page(struct file *file, struct page *page)
 	if (f2fs_has_inline_data(inode))
 		ret = f2fs_read_inline_data(inode, page);
 	if (ret == -EAGAIN)
-		ret = f2fs_mpage_readpages(page_file_mapping(page),
-						NULL, page, 1, false);
+		ret = f2fs_mpage_readpages(page_file_mapping(page), NULL, page);
 	return ret;
 }
 
-static int f2fs_read_data_pages(struct file *file,
-			struct address_space *mapping,
-			struct list_head *pages, unsigned nr_pages)
+static void f2fs_readahead(struct readahead_control *rac)
 {
-	struct inode *inode = mapping->host;
-	struct page *page = list_last_entry(pages, struct page, lru);
+	struct inode *inode = rac->mapping->host;
 
-	trace_f2fs_readpages(inode, page, nr_pages);
+	trace_f2fs_readpages(inode, readahead_index(rac), readahead_count(rac));
 
 	if (!f2fs_is_compress_backend_ready(inode))
-		return 0;
+		return;
 
 	/* If the file has inline data, skip readpages */
 	if (f2fs_has_inline_data(inode))
-		return 0;
+		return;
 
-	return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages, true);
+	f2fs_mpage_readpages(rac->mapping, rac, NULL);
 }
 
 int f2fs_encrypt_one_page(struct f2fs_io_info *fio)
@@ -3805,7 +3796,7 @@ static void f2fs_swap_deactivate(struct file *file)
 
 const struct address_space_operations f2fs_dblock_aops = {
 	.readpage	= f2fs_read_data_page,
-	.readpages	= f2fs_read_data_pages,
+	.readahead	= f2fs_readahead,
 	.writepage	= f2fs_write_data_page,
 	.writepages	= f2fs_write_data_pages,
 	.write_begin	= f2fs_write_begin,

include/trace/events/f2fs.h

@@ -1376,9 +1376,9 @@ TRACE_EVENT(f2fs_writepages,
 
 TRACE_EVENT(f2fs_readpages,
 
-	TP_PROTO(struct inode *inode, struct page *page, unsigned int nrpage),
+	TP_PROTO(struct inode *inode, pgoff_t start, unsigned int nrpage),
 
-	TP_ARGS(inode, page, nrpage),
+	TP_ARGS(inode, start, nrpage),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
@@ -1390,7 +1390,7 @@ TRACE_EVENT(f2fs_readpages,
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
 		__entry->ino	= inode->i_ino;
-		__entry->start	= page->index;
+		__entry->start	= start;
 		__entry->nrpage	= nrpage;
 	),