ext4: Change remaining tracepoints to use folio

ext4_readpage() is converted to ext4_read_folio() hence change the
related tracepoint from trace_ext4_readpage(page) to
trace_ext4_read_folio(folio). Do the same for
trace_ext4_releasepage(page) to trace_ext4_release_folio(folio)

As a minor bit of optimization to avoid an extra dereferencing,
since both of the above functions already were dereferencing
folio->mapping->host, hence change the tracepoint argument to take
(inode, folio).
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/caba2b3c0147bed4ea7706767dc1d19cd0e29ab0.1684122756.git.ritesh.list@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/inode.c

@@ -3105,7 +3105,7 @@ static int ext4_read_folio(struct file *file, struct folio *folio)
 	int ret = -EAGAIN;
 	struct inode *inode = folio->mapping->host;
 
-	trace_ext4_readpage(&folio->page);
+	trace_ext4_read_folio(inode, folio);
 
 	if (ext4_has_inline_data(inode))
 		ret = ext4_readpage_inline(inode, folio);
@@ -3164,9 +3164,10 @@ static void ext4_journalled_invalidate_folio(struct folio *folio,
 
 static bool ext4_release_folio(struct folio *folio, gfp_t wait)
 {
-	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
+	struct inode *inode = folio->mapping->host;
+	journal_t *journal = EXT4_JOURNAL(inode);
 
-	trace_ext4_releasepage(&folio->page);
+	trace_ext4_release_folio(inode, folio);
 
 	/* Page has dirty journalled data -> cannot release */
 	if (folio_test_checked(folio))

include/trace/events/ext4.h

@@ -560,10 +560,10 @@ TRACE_EVENT(ext4_writepages_result,
 		  (unsigned long) __entry->writeback_index)
 );
 
-DECLARE_EVENT_CLASS(ext4__page_op,
-	TP_PROTO(struct page *page),
+DECLARE_EVENT_CLASS(ext4__folio_op,
+	TP_PROTO(struct inode *inode, struct folio *folio),
 
-	TP_ARGS(page),
+	TP_ARGS(inode, folio),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,	dev			)
@@ -573,29 +573,29 @@ DECLARE_EVENT_CLASS(ext4__page_op,
 	),
 
 	TP_fast_assign(
-		__entry->dev	= page->mapping->host->i_sb->s_dev;
-		__entry->ino	= page->mapping->host->i_ino;
-		__entry->index	= page->index;
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->ino	= inode->i_ino;
+		__entry->index	= folio->index;
 	),
 
-	TP_printk("dev %d,%d ino %lu page_index %lu",
+	TP_printk("dev %d,%d ino %lu folio_index %lu",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino,
 		  (unsigned long) __entry->index)
 );
 
-DEFINE_EVENT(ext4__page_op, ext4_readpage,
+DEFINE_EVENT(ext4__folio_op, ext4_read_folio,
 
-	TP_PROTO(struct page *page),
+	TP_PROTO(struct inode *inode, struct folio *folio),
 
-	TP_ARGS(page)
+	TP_ARGS(inode, folio)
 );
 
-DEFINE_EVENT(ext4__page_op, ext4_releasepage,
+DEFINE_EVENT(ext4__folio_op, ext4_release_folio,
 
-	TP_PROTO(struct page *page),
+	TP_PROTO(struct inode *inode, struct folio *folio),
 
-	TP_ARGS(page)
+	TP_ARGS(inode, folio)
 );
 
 DECLARE_EVENT_CLASS(ext4_invalidate_folio_op,