From 621c9dac0eea7607cb9a57cc9ba47fbcd4e644c9 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Fri, 7 Aug 2020 15:42:31 +0800 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200807074238.1632519-13-boqun.feng@gmail.com --- 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 6644974a4f5a..b87766e080f5 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2808,16 +2808,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, if (!check_irq_usage(curr, prev, next)) 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 -> dependency already present? * @@ -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;