在 2023/4/25 22:09, Liam R. Howlett 写道:
When there is a single entry tree (range of 0-0 pointing to an entry),
then ensure the limit is either 0-0 or 1-oo, depending on where the user
walks. Ensure the correct node setting as well; either MAS_ROOT or
MAS_NONE.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
lib/maple_tree.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 20f0a10dc5608..31cbfd7b44728 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5099,24 +5099,25 @@ void *mas_walk(struct ma_state *mas)
{
void *entry;
+ if (mas_is_none(mas) || mas_is_paused(mas))
+ mas->node = MAS_START;
retry:
entry = mas_state_walk(mas);
- if (mas_is_start(mas))
+ if (mas_is_start(mas)) {
goto retry;
-
- if (mas_is_ptr(mas)) {
+ } else if (mas_is_none(mas)) {
+ mas->index = 0;
+ mas->last = ULONG_MAX;
+ } else if (mas_is_ptr(mas)) {
if (!mas->index) {
mas->last = 0;
- } else {
- mas->index = 1;
- mas->last = ULONG_MAX;
+ return mas_root(mas);
Why we call mas_root() to get the single entry stored in root again?
I think it's not safe. In RCU mode, if someone modify the tree to a
normal tree(not a single entry tree), mas_root() will return a address.
So, this may cause a race bug. We can return entry directly.
}
- return entry;
- }
- if (mas_is_none(mas)) {
- mas->index = 0;
+ mas->index = 1;
mas->last = ULONG_MAX;
+ mas->node = MAS_NONE;
+ return NULL;
}
return entry;
