squashfs: Convert squashfs to read_folio

This is a "weak" conversion which converts straight back to using pages.
A full conversion should be performed at some point, hopefully by
someone familiar with the filesystem.

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>

fs/squashfs/file.c

···
 	return 0;
 }
 
-static int squashfs_readpage(struct file *file, struct page *page)
+static int squashfs_read_folio(struct file *file, struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct inode *inode = page->mapping->host;
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
 	int index = page->index >> (msblk->block_log - PAGE_SHIFT);
···
 
 
 const struct address_space_operations squashfs_aops = {
-	.readpage = squashfs_readpage
+	.read_folio = squashfs_read_folio
 };

fs/squashfs/super.c

···
 
 	/*
 	 * squashfs provides 'backing_dev_info' in order to disable read-ahead. For
-	 * squashfs, I/O is not deferred, it is done immediately in readpage,
+	 * squashfs, I/O is not deferred, it is done immediately in read_folio,
 	 * which means the user would always have to wait their own I/O. So the effect
 	 * of readahead is very weak for squashfs. squashfs_bdi_init will set
 	 * sb->s_bdi->ra_pages and sb->s_bdi->io_pages to 0 and close readahead for

fs/squashfs/symlink.c

···
 #include "squashfs.h"
 #include "xattr.h"
 
-static int squashfs_symlink_readpage(struct file *file, struct page *page)
+static int squashfs_symlink_read_folio(struct file *file, struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct inode *inode = page->mapping->host;
 	struct super_block *sb = inode->i_sb;
 	struct squashfs_sb_info *msblk = sb->s_fs_info;
···
 
 
 const struct address_space_operations squashfs_symlink_aops = {
-	.readpage = squashfs_symlink_readpage
+	.read_folio = squashfs_symlink_read_folio
 };
 
 const struct inode_operations squashfs_symlink_inode_ops = {