From: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> commit fad8e4291da5e3243e086622df63cb952db444d8 upstream. Stop using maple state min/max for the range by passing through pointers for those values. This will allow the maple state to be reused without resetting. Also add some logic to fail out early on searching with invalid arguments. Link: https://lkml.kernel.org/r/20230414145728.4067069-1-Liam.Howlett@xxxxxxxxxx Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Reported-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4968,7 +4968,8 @@ not_found: * Return: True if found in a leaf, false otherwise. * */ -static bool mas_rev_awalk(struct ma_state *mas, unsigned long size) +static bool mas_rev_awalk(struct ma_state *mas, unsigned long size, + unsigned long *gap_min, unsigned long *gap_max) { enum maple_type type = mte_node_type(mas->node); struct maple_node *node = mas_mn(mas); @@ -5033,8 +5034,8 @@ static bool mas_rev_awalk(struct ma_stat if (unlikely(ma_is_leaf(type))) { mas->offset = offset; - mas->min = min; - mas->max = min + gap - 1; + *gap_min = min; + *gap_max = min + gap - 1; return true; } @@ -5310,6 +5311,9 @@ int mas_empty_area(struct ma_state *mas, unsigned long *pivots; enum maple_type mt; + if (min >= max) + return -EINVAL; + if (mas_is_start(mas)) mas_start(mas); else if (mas->offset >= 2) @@ -5364,6 +5368,9 @@ int mas_empty_area_rev(struct ma_state * { struct maple_enode *last = mas->node; + if (min >= max) + return -EINVAL; + if (mas_is_start(mas)) { mas_start(mas); mas->offset = mas_data_end(mas); @@ -5383,7 +5390,7 @@ int mas_empty_area_rev(struct ma_state * mas->index = min; mas->last = max; - while (!mas_rev_awalk(mas, size)) { + while (!mas_rev_awalk(mas, size, &min, &max)) { if (last == mas->node) { if (!mas_rewind_node(mas)) return -EBUSY; @@ -5398,17 +5405,9 @@ int mas_empty_area_rev(struct ma_state * if (unlikely(mas->offset == MAPLE_NODE_SLOTS)) return -EBUSY; - /* - * mas_rev_awalk() has set mas->min and mas->max to the gap values. If - * the maximum is outside the window we are searching, then use the last - * location in the search. - * mas->max and mas->min is the range of the gap. - * mas->index and mas->last are currently set to the search range. - */ - /* Trim the upper limit to the max. */ - if (mas->max <= mas->last) - mas->last = mas->max; + if (max <= mas->last) + mas->last = max; mas->index = mas->last - size + 1; return 0;
