From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Fri, 30 Nov 2018 21:12:16 +0000 (-0500)
Subject: maple_tree: Move idx-- and add a few comments
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=610d8ee0f18429f12f778e277c783642be2ade3f;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Move idx-- and add a few comments

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 2429cff63807..b79c39645baf 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -167,7 +167,7 @@ static void *_maple_walk(struct maple_state *ms)
 	/* Outside this nodes range, it doesn't exist. */
 	if (ms->min > ms->index ||
 	    ms->max < ms->index)
-		return entry;
+		return entry; // FIXME: Retry?
 
 	if (ms->node == NULL)
 		return entry;
@@ -197,6 +197,7 @@ static void *_maple_walk(struct maple_state *ms)
 static inline int _count_node_64(struct maple_state *ms) {
 	int i;
 	struct maple_node_64 mn64 = _maple_to_node(ms->node)->map64;
+
 	for (i = 0; i < MAPLE_NODE64_MAX_PIVOT; i++) {
 		if (mn64.pivot[i] == 0)
 			break;
@@ -389,9 +390,9 @@ static inline int _maple_insert_64(struct maple_state *ms, void *entry)
 	idx = p_here + shift;
 	mn64->pivot[idx] = ms->end + 1;
 	rcu_assign_pointer(mn64->slot[idx], entry);
-	idx--;
 
 	if (shift > 0) {
+		idx--;
 		mn64->pivot[idx] = ms->index;
 		rcu_assign_pointer(mn64->slot[idx], NULL);
 	}
@@ -460,6 +461,7 @@ static void *_maple_insert_walk(struct maple_state *ms)
 		ms->node = entry;
 		_maple_update_limits(ms);
 		if(_maple_is_node_4(ms)) {
+			/* FIXME: What about range inserts on a node4? */
 			entry = _maple_walk_4(ms);
 			/* end of the line.. */
 			continue;
@@ -473,7 +475,7 @@ static void *_maple_insert_walk(struct maple_state *ms)
 			 */
 			if (ret == -ENOMEM)
 				return maple_retry(ms);
-			if (ret == -EINVAL) // FIXME..
+			if (ret == -EINVAL) // FIXME: root expand on split may return an invalid insert.
 				return maple_retry(ms);
 			return NULL;
 		}
@@ -488,7 +490,7 @@ static void *_maple_insert_walk(struct maple_state *ms)
 			struct maple_node *mn = ms->node;
 			entry = _maple_walk_64(ms, ms->end);
 			if (s_idx != ms->slot_idx || mn != ms->node)
-				return mn;
+				return mn; /* Return non-NULL for an insert fail */
 		}
 
 	} while(xa_is_internal(entry));