6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> commit fec29364348fec535c55708b1f4025b321aba572 upstream. mas_prealloc() may walk partially down the tree before finding that a split or spanning store is needed. When the write occurs, relax the logic on resetting the walk so that partial walks will not restart, but walks that have gone too far (a store that affects beyond the current node) should be restarted. Link: https://lkml.kernel.org/r/20230724183157.3939892-15-Liam.Howlett@xxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Cc: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5439,19 +5439,34 @@ static inline void mte_destroy_walk(stru static void mas_wr_store_setup(struct ma_wr_state *wr_mas) { + if (mas_is_start(wr_mas->mas)) + return; + if (unlikely(mas_is_paused(wr_mas->mas))) - mas_reset(wr_mas->mas); + goto reset; + + if (unlikely(mas_is_none(wr_mas->mas))) + goto reset; + + /* + * A less strict version of mas_is_span_wr() where we allow spanning + * writes within this node. This is to stop partial walks in + * mas_prealloc() from being reset. + */ + if (wr_mas->mas->last > wr_mas->mas->max) + goto reset; + + if (wr_mas->entry) + return; + + if (mte_is_leaf(wr_mas->mas->node) && + wr_mas->mas->last == wr_mas->mas->max) + goto reset; + + return; - if (!mas_is_start(wr_mas->mas)) { - if (mas_is_none(wr_mas->mas)) { - mas_reset(wr_mas->mas); - } else { - wr_mas->r_max = wr_mas->mas->max; - wr_mas->type = mte_node_type(wr_mas->mas->node); - if (mas_is_span_wr(wr_mas)) - mas_reset(wr_mas->mas); - } - } +reset: + mas_reset(wr_mas->mas); } /* Interface */
