mm: give the 'ret' variable a better name __do_page_cache_readahead

It counts the number of pages acted on, so name it nr_pages to make that
obvious.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

mm/readahead.c

@@ -156,7 +156,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 	unsigned long end_index;	/* The last page we want to read */
 	LIST_HEAD(page_pool);
 	int page_idx;
-	int ret = 0;
+	int nr_pages = 0;
 	loff_t isize = i_size_read(inode);
 	gfp_t gfp_mask = readahead_gfp_mask(mapping);
 
@@ -187,7 +187,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 		list_add(&page->lru, &page_pool);
 		if (page_idx == nr_to_read - lookahead_size)
 			SetPageReadahead(page);
-		ret++;
+		nr_pages++;
 	}
 
 	/*
@@ -195,11 +195,11 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 	 * uptodate then the caller will launch readpage again, and
 	 * will then handle the error.
 	 */
-	if (ret)
-		read_pages(mapping, filp, &page_pool, ret, gfp_mask);
+	if (nr_pages)
+		read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
 	BUG_ON(!list_empty(&page_pool));
 out:
-	return ret;
+	return nr_pages;
 }
 
 /*