在 2023/5/18 03:33, Liam R. Howlett 写道:
* Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [230517 04:59]:
Add comment for mas_wr_append(), move mas_update_gap() into
mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.
Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
---
lib/maple_tree.c | 33 ++++++++++++++++++++-------------
1 file changed, 20 insertions(+), 13 deletions(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 3b9d227f3d7d..bbe4c6f2858c 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4308,6 +4308,12 @@ static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
return new_end;
}
+/*
+ * mas_wr_append: Attempt to append
+ * @wr_mas: the maple write state
+ *
+ * Return: True if appended, false otherwise
+ */
static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
{
unsigned char end = wr_mas->node_end;
@@ -4315,7 +4321,11 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
struct ma_state *mas = wr_mas->mas;
unsigned char node_pivots = mt_pivots[wr_mas->type];
+ if (!(mas->offset == wr_mas->node_end))
+ return false;
+
if ((mas->index != wr_mas->r_min) && (mas->last == wr_mas->r_max)) {
+ /* Append to end of range */
if (new_end < node_pivots)
wr_mas->pivots[new_end] = wr_mas->pivots[end];
@@ -4323,13 +4333,10 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end);
rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->entry);
- mas->offset = new_end;
wr_mas->pivots[end] = mas->index - 1;
-
- return true;
- }
-
- if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
+ mas->offset = new_end;
+ } else if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
+ /* Append to start of range */
if (new_end < node_pivots)
wr_mas->pivots[new_end] = wr_mas->pivots[end];
@@ -4339,10 +4346,13 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
wr_mas->pivots[end] = mas->last;
rcu_assign_pointer(wr_mas->slots[end], wr_mas->entry);
- return true;
+ } else {
+ return false;
I don't think we can get here with your changes, what do you think? If
so, we can move the metadata setting to the outside of the if/else. I
checked by adding a BUG_ON() and the test code never gets here.
My thinking is, we know offset == node_end and new_end == node_end + 1..
so we must be inserting into the last slot and only adding one entry.
Yes, I'll address this in v3. Thanks.
}
- return false;
+ if (!wr_mas->content || !wr_mas->entry)
+ mas_update_gap(mas);
+ return true;
}
/*
@@ -4382,12 +4392,9 @@ static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
if (new_end >= mt_slots[wr_mas->type])
goto slow_path;
- if (wr_mas->entry && (wr_mas->node_end < mt_slots[wr_mas->type] - 1) &&
- (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) {
- if (!wr_mas->content || !wr_mas->entry)
- mas_update_gap(mas);
+ /* Attempt to append */
+ if (new_end == wr_mas->node_end + 1 && mas_wr_append(wr_mas))
return;
- }
if ((wr_mas->offset_end - mas->offset <= 1) && mas_wr_slot_store(wr_mas))
return;
--
2.20.1
