readahead: drop index argument of page_cache_async_readahead()

The index argument of page_cache_async_readahead() is just folio->index so
there's no point in passing is separately.  Drop it.

Link: https://lkml.kernel.org/r/20240625101909.12234-5-jack@suse.czSigned-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Zhang Peng <zhangpengpeng0808@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/btrfs/relocation.c

@@ -2975,8 +2975,7 @@ static int relocate_one_folio(struct inode *inode, struct file_ra_state *ra,
 
 	if (folio_test_readahead(folio))
 		page_cache_async_readahead(inode->i_mapping, ra, NULL,
-					   folio, index,
-					   last_index + 1 - index);
+					   folio, last_index + 1 - index);
 
 	if (!folio_test_uptodate(folio)) {
 		btrfs_read_folio(NULL, folio);

fs/btrfs/send.c

@@ -5307,7 +5307,7 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
 
 		if (folio_test_readahead(folio))
 			page_cache_async_readahead(mapping, &sctx->ra, NULL, folio,
-						   index, last_index + 1 - index);
+						   last_index + 1 - index);
 
 		if (!folio_test_uptodate(folio)) {
 			btrfs_read_folio(NULL, folio);

include/linux/pagemap.h

@@ -1293,8 +1293,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
  * @mapping: address_space which holds the pagecache and I/O vectors
  * @ra: file_ra_state which holds the readahead state
  * @file: Used by the filesystem for authentication.
- * @folio: The folio at @index which triggered the readahead call.
- * @index: Index of first page to be read.
+ * @folio: The folio which triggered the readahead call.
  * @req_count: Total number of pages being read by the caller.
  *
  * page_cache_async_readahead() should be called when a page is used which
@@ -1305,9 +1304,9 @@ void page_cache_sync_readahead(struct address_space *mapping,
 static inline
 void page_cache_async_readahead(struct address_space *mapping,
 		struct file_ra_state *ra, struct file *file,
-		struct folio *folio, pgoff_t index, unsigned long req_count)
+		struct folio *folio, unsigned long req_count)
 {
-	DEFINE_READAHEAD(ractl, file, ra, mapping, index);
+	DEFINE_READAHEAD(ractl, file, ra, mapping, folio->index);
 	page_cache_async_ra(&ractl, folio, req_count);
 }