Merge branch 'jk/clear-delta-base-cache-fix'

A crashing bug introduced in v2.11 timeframe has been found (it is
triggerable only in fast-import) and fixed.

* jk/clear-delta-base-cache-fix:
  clear_delta_base_cache(): don't modify hashmap while iterating

Documentation/technical/api-hashmap.txt

@@ -188,7 +188,9 @@ Returns the removed entry, or NULL if not found.
 `void *hashmap_iter_next(struct hashmap_iter *iter)`::
 `void *hashmap_iter_first(struct hashmap *map, struct hashmap_iter *iter)`::
 
-	Used to iterate over all entries of a hashmap.
+	Used to iterate over all entries of a hashmap. Note that it is
+	not safe to add or remove entries to the hashmap while
+	iterating.
 +
 `hashmap_iter_init` initializes a `hashmap_iter` structure.
 +

sha1_file.c

@@ -2371,11 +2371,10 @@ static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
 
 void clear_delta_base_cache(void)
 {
-	struct hashmap_iter iter;
-	struct delta_base_cache_entry *entry;
-	for (entry = hashmap_iter_first(&delta_base_cache, &iter);
-	     entry;
-	     entry = hashmap_iter_next(&iter)) {
+	struct list_head *lru, *tmp;
+	list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
+		struct delta_base_cache_entry *entry =
+			list_entry(lru, struct delta_base_cache_entry, lru);
 		release_delta_base_cache(entry);
 	}
 }