diff options
| author | Shuah Khan <skhan@linuxfoundation.org> | 2021-02-26 17:06:58 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 12:51:05 +0100 |
| commit | 3e31f94752e454bdd0ca4a1d046ee21f80c166c5 (patch) | |
| tree | fb22b7e8bbf18565fe2557937ae68410458a7297 /kernel/locking | |
| parent | 864b435514b286c0be2a38a02f487aa28d990ef8 (diff) | |
| download | linux-3e31f94752e454bdd0ca4a1d046ee21f80c166c5.tar.bz2 | |
lockdep: Add lockdep_assert_not_held()
Some kernel functions must be called without holding a specific lock.
Add lockdep_assert_not_held() to be used in these functions to detect
incorrect calls while holding a lock.
lockdep_assert_not_held() provides the opposite functionality of
lockdep_assert_held() which is used to assert calls that require
holding a specific lock.
Incorporates suggestions from Peter Zijlstra to avoid misfires when
lockdep_off() is employed.
The need for lockdep_assert_not_held() came up in a discussion on
ath10k patch. ath10k_drain_tx() and i915_vma_pin_ww() are examples
of functions that can use lockdep_assert_not_held().
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c6d0c1dc6253..969736b33185 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5539,8 +5539,12 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read) unsigned long flags; int ret = 0; + /* + * Avoid false negative lockdep_assert_held() and + * lockdep_assert_not_held(). + */ if (unlikely(!lockdep_enabled())) - return 1; /* avoid false negative lockdep_assert_held() */ + return -1; raw_local_irq_save(flags); check_flags(flags); |