Lock exclusiveness table gathers the information about whether two lock acquisitions for the same lock instance can be granted concurrently.
Signed-off-by: Yuyang Du <duyuy...@gmail.com> --- kernel/locking/lockdep.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index cb3a1d3..e11ffab 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -894,6 +894,36 @@ static bool class_lock_list_valid(struct lock_class *c, int forward) #ifdef CONFIG_PROVE_LOCKING static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; static u16 chain_hlocks_type[MAX_LOCKDEP_CHAIN_HLOCKS]; + +/* + * Lock exclusiveness table. + * + * With lock X.A and X.B (X.A is on top and X.B is on bottom): + * + * T1 TB T1 TB + * -- -- -- -- + * + * X.A or X.A + * X.B X.B + * + * in the table Yes means the two locks are exclusive and No otherwise. + * + * +---------------------+------------+-----------+---------------------+ + * | X.A vs. X.B | Write lock | Read lock | Recursive-read lock | + * +---------------------+------------+-----------+---------------------+ + * | Write lock | Yes | Yes | Yes | + * +---------------------+------------+-----------+---------------------+ + * | Read lock | Yes | Yes | No | + * +---------------------+------------+-----------+---------------------+ + * | Recursive-read lock | Yes | Yes | No | + * +---------------------+------------+-----------+---------------------+ + * + */ +static int lock_excl_table[3][3] = { + {1, 1, 1}, /* Write lock vs. X.B */ + {1, 1, 0}, /* Read lock vs. X.B */ + {1, 1, 0}, /* Recursive-read lock vs. X.B */ +}; #endif static bool check_lock_chain_key(struct lock_chain *chain) -- 1.8.3.1