[PATCH] maple_tree: exchange entry1/entry2 to make seen_entry2 do see new value

[PATCH] maple_tree: exchange entry1/entry2 to make seen_entry2 do see new value

[Wei Yang]

During run_check_rcu() and run_check_rcu_slowread(), we would write
entry2/entry3 to specified range and eval_rcu_entry() would test whether
these value is seen by reader.

So we have three entries in struct rcu_test_struct:

  * entry1: the original value during tree initialization
  * entry2/entry3: value to be written

Currently we set entry2 to the original value, this would fool
eval_rcu_entry() to see entry2 even there is no writer.

Exchange entry1/entry2 to make seen_entry2 do see new value.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
 tools/testing/radix-tree/maple.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
index 1e293e4d856d..fc6578f81cb0 100644
--- a/tools/testing/radix-tree/maple.c
+++ b/tools/testing/radix-tree/maple.c
@@ -35323,8 +35323,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
 	vals.mt = mt;
 	vals.index = 4390;
 	vals.last = 4398;
-	vals.entry1 = xa_mk_value(4390);
-	vals.entry2 = xa_mk_value(439);
+	vals.entry1 = xa_mk_value(439);
+	vals.entry2 = xa_mk_value(4390);
 	vals.entry3 = xa_mk_value(439);
 	vals.seen_entry2 = 0;
 	vals.range_start = 4316;
@@ -35360,8 +35360,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
 	vals.mt = mt;
 	vals.index = 4390;
 	vals.last = 4398;
-	vals.entry1 = xa_mk_value(4390);
-	vals.entry2 = xa_mk_value(439);
+	vals.entry1 = xa_mk_value(439);
+	vals.entry2 = xa_mk_value(4390);
 	vals.entry3 = xa_mk_value(4391);
 	vals.seen_toggle = 0;
 	vals.seen_added = 0;
-- 
2.34.1

Re: [PATCH] maple_tree: exchange entry1/entry2 to make seen_entry2 do see new value

[Liam R. Howlett]

* Wei Yang <richard.weiyang@gmail.com> [250407 22:10]:
> During run_check_rcu() and run_check_rcu_slowread(), we would write
> entry2/entry3 to specified range and eval_rcu_entry() would test whether
> these value is seen by reader.
> 
> So we have three entries in struct rcu_test_struct:
> 
>   * entry1: the original value during tree initialization
>   * entry2/entry3: value to be written
> 
> Currently we set entry2 to the original value, this would fool
> eval_rcu_entry() to see entry2 even there is no writer.
> 
> Exchange entry1/entry2 to make seen_entry2 do see new value.
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> CC: Liam R. Howlett <Liam.Howlett@Oracle.com>

Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

> ---
>  tools/testing/radix-tree/maple.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> index 1e293e4d856d..fc6578f81cb0 100644
> --- a/tools/testing/radix-tree/maple.c
> +++ b/tools/testing/radix-tree/maple.c
> @@ -35323,8 +35323,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
>  	vals.mt = mt;
>  	vals.index = 4390;
>  	vals.last = 4398;
> -	vals.entry1 = xa_mk_value(4390);
> -	vals.entry2 = xa_mk_value(439);
> +	vals.entry1 = xa_mk_value(439);
> +	vals.entry2 = xa_mk_value(4390);
>  	vals.entry3 = xa_mk_value(439);
>  	vals.seen_entry2 = 0;
>  	vals.range_start = 4316;
> @@ -35360,8 +35360,8 @@ static noinline void __init check_rcu_threaded(struct maple_tree *mt)
>  	vals.mt = mt;
>  	vals.index = 4390;
>  	vals.last = 4398;
> -	vals.entry1 = xa_mk_value(4390);
> -	vals.entry2 = xa_mk_value(439);
> +	vals.entry1 = xa_mk_value(439);
> +	vals.entry2 = xa_mk_value(4390);
>  	vals.entry3 = xa_mk_value(4391);
>  	vals.seen_toggle = 0;
>  	vals.seen_added = 0;
> -- 
> 2.34.1
>