* Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> [230512 11:54]:
> * Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [230509 08:39]:
> >
> >
> > 在 2023/5/6 01:42, 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 f060c71965c0d..914399519cf54 100644
> > > --- a/lib/maple_tree.c
> > > +++ b/lib/maple_tree.c
> > > @@ -5022,24 +5022,25 @@ void *mas_walk(struct ma_state *mas)
> > > {
> > > void *entry;
> > > + if (mas_is_none(mas) || mas_is_paused(mas))
> > if (mas_is_none(mas) || mas_is_paused(mas) || mas_is_ptr(mas))
> > > + mas->node = MAS_START;
> >
> > Hi, Liam
> > There is an issue that it cannot pass the user space test program
> > with this patchset.
> > I tested it based on 47cba14ce6fc4(linux-next/master).
> >
> > The reason is that mas_walk() does not handle the state that mas is
> > root. The root cause is that mas_start() only handles the start state,
> > and returns NULL for the root state. When encountering the root state,
> > we can reset to start so that it is handled in mas_start().
>
> Thanks. I'll have a look and adjust v3.
This was introduced with the fix for the race condition between v1 and
v2.
It is probably best to reset to MAS_START instead of the potential stale
data.
>
> >
> > log:
> > BUG at check_state_handling:3076 (1)
> > maple_tree(0x55d6a9838ca0) flags 1, height 0 root 0x1234500
> > 0: 0x1234500
> > Pass: 453406336 Run:453406337
> > maple: ../../../lib/test_maple_tree.c:3076: check_state_handling: Assertion
> > `0' failed.
> > Aborted (core dumped)
> > > 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 entry;
> > > }
> > > - 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;
