use pop_commit() for consuming the first entry of a struct commit_list

index 4ba7f28..846004b 100644
@@ -537,7 +537,7 @@ static void fmt_merge_msg_sigs(struct strbuf *out)
 static void find_merge_parents(struct merge_parents *result,
 			       struct strbuf *in, unsigned char *head)
 {
-	struct commit_list *parents, *next;
+	struct commit_list *parents;
 	struct commit *head_commit;
 	int pos = 0, i, j;
 

@@ -576,13 +576,10 @@ static void find_merge_parents(struct merge_parents *result,
 	parents = reduce_heads(parents);
 
 	while (parents) {
+		struct commit *cmit = pop_commit(&parents);
 		for (i = 0; i < result->nr; i++)
-			if (!hashcmp(result->item[i].commit,
-				     parents->item->object.sha1))
+			if (!hashcmp(result->item[i].commit, cmit->object.sha1))
 				result->item[i].used = 1;
-		next = parents->next;
-		free(parents);
-		parents = next;
 	}
 
 	for (i = j = 0; i < result->nr; i++) {

index a0a9328..31241b8 100644
@@ -1019,7 +1019,7 @@ static struct commit_list *reduce_parents(struct commit *head_commit,
 					  int *head_subsumed,
 					  struct commit_list *remoteheads)
 {
-	struct commit_list *parents, *next, **remotes = &remoteheads;
+	struct commit_list *parents, **remotes;
 
 	/*
 	 * Is the current HEAD reachable from another commit being

@@ -1033,16 +1033,14 @@ static struct commit_list *reduce_parents(struct commit *head_commit,
 	/* Find what parents to record by checking independent ones. */
 	parents = reduce_heads(remoteheads);
 
-	for (remoteheads = NULL, remotes = &remoteheads;
-	     parents;
-	     parents = next) {
-		struct commit *commit = parents->item;
-		next = parents->next;
+	remoteheads = NULL;
+	remotes = &remoteheads;
+	while (parents) {
+		struct commit *commit = pop_commit(&parents);
 		if (commit == head_commit)
 			*head_subsumed = 0;
 		else
 			remotes = &commit_list_insert(commit, remotes)->next;
-		free(parents);
 	}
 	return remoteheads;
 }

index f96ca2a..cf1145e 100644
@@ -218,7 +218,6 @@ static int keep_entry(struct commit **it, unsigned char *sha1)
  */
 static void mark_reachable(struct expire_reflog_policy_cb *cb)
 {
-	struct commit *commit;
 	struct commit_list *pending;
 	unsigned long expire_limit = cb->mark_limit;
 	struct commit_list *leftover = NULL;

@@ -228,11 +227,8 @@ static void mark_reachable(struct expire_reflog_policy_cb *cb)
 
 	pending = cb->mark_list;
 	while (pending) {
-		struct commit_list *entry = pending;
 		struct commit_list *parent;
-		pending = entry->next;
-		commit = entry->item;
-		free(entry);
+		struct commit *commit = pop_commit(&pending);
 		if (commit->object.flags & REACHABLE)
 			continue;
 		if (parse_commit(commit))

index 02d747d..e92a782 100644
@@ -281,11 +281,8 @@ static int try_difference(const char *arg)
 			b = lookup_commit_reference(end);
 			exclude = get_merge_bases(a, b);
 			while (exclude) {
-				struct commit_list *n = exclude->next;
-				show_rev(REVERSED,
-					 exclude->item->object.sha1,NULL);
-				free(exclude);
-				exclude = n;
+				struct commit *commit = pop_commit(&exclude);
+				show_rev(REVERSED, commit->object.sha1, NULL);
 			}
 		}
 		*dotdot = '.';

index 092b59b..ac5141d 100644
@@ -53,17 +53,6 @@ static struct commit *interesting(struct commit_list *list)
 	return NULL;
 }
 
-static struct commit *pop_one_commit(struct commit_list **list_p)
-{
-	struct commit *commit;
-	struct commit_list *list;
-	list = *list_p;
-	commit = list->item;
-	*list_p = list->next;
-	free(list);
-	return commit;
-}
-
 struct commit_name {
 	const char *head_name; /* which head's ancestor? */
 	int generation; /* how many parents away from head_name */

@@ -213,7 +202,7 @@ static void join_revs(struct commit_list **list_p,
 	while (*list_p) {
 		struct commit_list *parents;
 		int still_interesting = !!interesting(*list_p);
-		struct commit *commit = pop_one_commit(list_p);
+		struct commit *commit = pop_commit(list_p);
 		int flags = commit->object.flags & all_mask;
 
 		if (!still_interesting && extra <= 0)

@@ -504,7 +493,7 @@ static int show_merge_base(struct commit_list *seen, int num_rev)
 	int exit_status = 1;
 
 	while (seen) {
-		struct commit *commit = pop_one_commit(&seen);
+		struct commit *commit = pop_commit(&seen);
 		int flags = commit->object.flags & all_mask;
 		if (!(flags & UNINTERESTING) &&
 		    ((flags & all_revs) == all_revs)) {

@@ -929,7 +918,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 	all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
 
 	while (seen) {
-		struct commit *commit = pop_one_commit(&seen);
+		struct commit *commit = pop_commit(&seen);
 		int this_flag = commit->object.flags;
 		int is_merge_point = ((this_flag & all_revs) == all_revs);
 

index 494615d..d1810c9 100644
@@ -455,11 +455,8 @@ struct commit_list *copy_commit_list(struct commit_list *list)
 
 void free_commit_list(struct commit_list *list)
 {
-	while (list) {
-		struct commit_list *temp = list;
-		list = temp->next;
-		free(temp);
-	}
+	while (list)
+		pop_commit(&list);
 }
 
 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)

@@ -505,12 +502,8 @@ void commit_list_sort_by_date(struct commit_list **list)
 struct commit *pop_most_recent_commit(struct commit_list **list,
 				      unsigned int mark)
 {
-	struct commit *ret = (*list)->item;
+	struct commit *ret = pop_commit(list);
 	struct commit_list *parents = ret->parents;
-	struct commit_list *old = *list;
-
-	*list = (*list)->next;
-	free(old);
 
 	while (parents) {
 		struct commit *commit = parents->item;

@@ -861,11 +854,9 @@ static struct commit_list *merge_bases_many(struct commit *one, int n, struct co
 	list = paint_down_to_common(one, n, twos);
 
 	while (list) {
-		struct commit_list *next = list->next;
-		if (!(list->item->object.flags & STALE))
-			commit_list_insert_by_date(list->item, &result);
-		free(list);
-		list = next;
+		struct commit *commit = pop_commit(&list);
+		if (!(commit->object.flags & STALE))
+			commit_list_insert_by_date(commit, &result);
 	}
 	return result;
 }

@@ -1546,13 +1537,9 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	 * if everything else stays the same.
 	 */
 	while (parents) {
-		struct commit_list *next = parents->next;
-		struct commit *parent = parents->item;
-
+		struct commit *parent = pop_commit(&parents);
 		strbuf_addf(&buffer, "parent %s\n",
 			    sha1_to_hex(parent->object.sha1));
-		free(parents);
-		parents = next;
 	}
 
 	/* Person/date information */

index 1101f82..977e34e 100644
@@ -1938,10 +1938,8 @@ int resolve_remote_symref(struct ref *ref, struct ref *list)
 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 {
 	while (list) {
-		struct commit_list *temp = list;
-		temp->item->object.flags &= ~mark;
-		list = temp->next;
-		free(temp);
+		struct commit *commit = pop_commit(&list);
+		commit->object.flags &= ~mark;
 	}
 }
 

index 2236463..0fbb684 100644
@@ -153,10 +153,7 @@ void mark_parents_uninteresting(struct commit *commit)
 		commit_list_insert(l->item, &parents);
 
 	while (parents) {
-		struct commit *commit = parents->item;
-		l = parents;
-		parents = parents->next;
-		free(l);
+		struct commit *commit = pop_commit(&parents);
 
 		while (commit) {
 			/*

@@ -1102,14 +1099,10 @@ static int limit_list(struct rev_info *revs)
 	}
 
 	while (list) {
-		struct commit_list *entry = list;
-		struct commit *commit = list->item;
+		struct commit *commit = pop_commit(&list);
 		struct object *obj = &commit->object;
 		show_early_output_fn_t show;
 
-		list = list->next;
-		free(entry);
-
 		if (commit == interesting_cache)
 			interesting_cache = NULL;
 

@@ -2733,10 +2726,7 @@ static void simplify_merges(struct rev_info *revs)
 		yet_to_do = NULL;
 		tail = &yet_to_do;
 		while (list) {
-			commit = list->item;
-			next = list->next;
-			free(list);
-			list = next;
+			commit = pop_commit(&list);
 			tail = simplify_one(revs, commit, tail);
 		}
 	}

@@ -2748,10 +2738,7 @@ static void simplify_merges(struct rev_info *revs)
 	while (list) {
 		struct merge_simplify_state *st;
 
-		commit = list->item;
-		next = list->next;
-		free(list);
-		list = next;
+		commit = pop_commit(&list);
 		st = locate_simplify_state(revs, commit);
 		if (st->simplified == commit)
 			tail = &commit_list_insert(commit, tail)->next;

@@ -3125,11 +3112,7 @@ static struct commit *get_revision_1(struct rev_info *revs)
 		return NULL;
 
 	do {
-		struct commit_list *entry = revs->commits;
-		struct commit *commit = entry->item;
-
-		revs->commits = entry->next;
-		free(entry);
+		struct commit *commit = pop_commit(&revs->commits);
 
 		if (revs->reflog_info) {
 			save_parents(revs, commit);

index d49a3d6..4dcb454 100644
@@ -401,13 +401,9 @@ static void paint_down(struct paint_info *info, const unsigned char *sha1,
 	commit_list_insert(c, &head);
 	while (head) {
 		struct commit_list *p;
-		struct commit *c = head->item;
+		struct commit *c = pop_commit(&head);
 		uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 
-		p = head;
-		head = head->next;
-		free(p);
-
 		/* XXX check "UNINTERESTING" from pack bitmaps if available */
 		if (c->object.flags & (SEEN | UNINTERESTING))
 			continue;

index 89e832b..d0bc3ca 100644
@@ -316,10 +316,8 @@ static int reachable(struct commit *want)
 
 	commit_list_insert_by_date(want, &work);
 	while (work) {
-		struct commit_list *list = work->next;
-		struct commit *commit = work->item;
-		free(work);
-		work = list;
+		struct commit_list *list;
+		struct commit *commit = pop_commit(&work);
 
 		if (commit->object.flags & THEY_HAVE) {
 			want->object.flags |= COMMON_KNOWN;