The following commit has been merged into the locking/core branch of tip: Commit-ID: 621c9dac0eea7607cb9a57cc9ba47fbcd4e644c9 Gitweb: https://git.kernel.org/tip/621c9dac0eea7607cb9a57cc9ba47fbcd4e644c9 Author: Boqun Feng <[email protected]> AuthorDate: Fri, 07 Aug 2020 15:42:31 +08:00 Committer: Peter Zijlstra <[email protected]> CommitterDate: Wed, 26 Aug 2020 12:42:06 +02:00
lockdep: Add recursive read locks into dependency graph Since we have all the fundamental to handle recursive read locks, we now add them into the dependency graph. Signed-off-by: Boqun Feng <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- kernel/locking/lockdep.c | 19 ++----------------- 1 file changed, 2 insertions(+), 17 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 6644974..b87766e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2809,16 +2809,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, return 0; /* - * For recursive read-locks we do all the dependency checks, - * but we dont store read-triggered dependencies (only - * write-triggered dependencies). This ensures that only the - * write-side dependencies matter, and that if for example a - * write-lock never takes any other locks, then the reads are - * equivalent to a NOP. - */ - if (next->read == 2 || prev->read == 2) - return 1; - /* * Is the <prev> -> <next> dependency already present? * * (this may occur even though this is a new chain: consider @@ -2935,13 +2925,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) u16 distance = curr->lockdep_depth - depth + 1; hlock = curr->held_locks + depth - 1; - /* - * Only non-recursive-read entries get new dependencies - * added: - */ - if (hlock->read != 2 && hlock->check) { - int ret = check_prev_add(curr, hlock, next, distance, - &trace); + if (hlock->check) { + int ret = check_prev_add(curr, hlock, next, distance, &trace); if (!ret) return 0;
