diff --git a/lib/attr.c b/lib/attr.c
index 0e63f1b6de..1acb4ef430 100644
--- a/lib/attr.c
+++ b/lib/attr.c
@@ -793,7 +793,7 @@ static struct attr_stack *read_attr_from_index(struct index_state *istate,
 {
 	struct attr_stack *stack = NULL;
 	char *buf;
-	unsigned long size;
+	size_t size;
 	int sparse_dir_pos = -1;
 
 	if (!istate)
diff --git a/lib/convert.c b/lib/convert.c
index 74d452b0de..77f06fcfdb 100644
--- a/lib/convert.c
+++ b/lib/convert.c
@@ -141,7 +141,7 @@ const char *get_cached_convert_stats_ascii(struct index_state *istate,
 					   const char *path)
 {
 	const char *ret;
-	unsigned long sz;
+	size_t sz;
 	void *data = read_blob_data_from_index(istate, path, &sz);
 	ret = gather_convert_stats_ascii(data, sz);
 	free(data);
@@ -223,7 +223,7 @@ static void check_global_conv_flags_eol(const char *path,
 
 static int has_crlf_in_index(struct index_state *istate, const char *path)
 {
-	unsigned long sz;
+	size_t sz;
 	void *data;
 	const char *crp;
 	int has_crlf = 0;
diff --git a/lib/read-cache-ll.h b/lib/read-cache-ll.h
index 71b87615eb..ab4b9f25b4 100644
--- a/lib/read-cache-ll.h
+++ b/lib/read-cache-ll.h
@@ -412,7 +412,7 @@ int chmod_index_entry(struct index_state *, struct cache_entry *ce, char flip);
 int ce_same_name(const struct cache_entry *a, const struct cache_entry *b);
 void set_object_name_for_intent_to_add_entry(struct cache_entry *ce);
 int index_name_is_other(struct index_state *, const char *, int);
-void *read_blob_data_from_index(struct index_state *, const char *, unsigned long *);
+void *read_blob_data_from_index(struct index_state *, const char *, size_t *);
 
 /* do stat comparison even if CE_VALID is true */
 #define CE_MATCH_IGNORE_VALID		01
diff --git a/lib/read-cache.c b/lib/read-cache.c
index 63313c8771..f77ff7387f 100644
--- a/lib/read-cache.c
+++ b/lib/read-cache.c
@@ -3473,7 +3473,7 @@ int index_name_is_other(struct index_state *istate, const char *name,
 }
 
 void *read_blob_data_from_index(struct index_state *istate,
-				const char *path, unsigned long *size)
+				const char *path, size_t *size)
 {
 	int pos, len;
 	size_t sz;
@@ -3504,7 +3504,7 @@ void *read_blob_data_from_index(struct index_state *istate,
 		return NULL;
 	}
 	if (size)
-		*size = cast_size_t_to_ulong(sz);
+		*size = sz;
 	return data;
 }