From 3e31f94752e454bdd0ca4a1d046ee21f80c166c5 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Fri, 26 Feb 2021 17:06:58 -0700 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/ --- include/linux/lockdep.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 7b7ebf2e28ec..dbd9ea846b36 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -301,8 +301,12 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) -#define lockdep_assert_held(l) do { \ - WARN_ON(debug_locks && !lockdep_is_held(l)); \ +#define lockdep_assert_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 0); \ + } while (0) + +#define lockdep_assert_not_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 1); \ } while (0) #define lockdep_assert_held_write(l) do { \ @@ -393,7 +397,8 @@ extern int lockdep_is_held(const void *); #define lockdep_is_held_type(l, r) (1) #define lockdep_assert_held(l) do { (void)(l); } while (0) -#define lockdep_assert_held_write(l) do { (void)(l); } while (0) +#define lockdep_assert_not_held(l) do { (void)(l); } while (0) +#define lockdep_assert_held_write(l) do { (void)(l); } while (0) #define lockdep_assert_held_read(l) do { (void)(l); } while (0) #define lockdep_assert_held_once(l) do { (void)(l); } while (0) -- cgit From f8cfa46608f8aa5ca5421ce281ab314129c15411 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Fri, 26 Feb 2021 17:06:59 -0700 Subject: lockdep: Add lockdep lock state defines Adds defines for lock state returns from lock_is_held_type() based on Johannes Berg's suggestions as it make it easier to read and maintain the lock states. These are defines and a enum to avoid changes to lock_is_held_type() and lockdep_is_held() return types. Updates to lock_is_held_type() and __lock_is_held() to use the new defines. Signed-off-by: Shuah Khan Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/ --- include/linux/lockdep.h | 11 +++++++++-- kernel/locking/lockdep.c | 11 ++++++----- 2 files changed, 15 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index dbd9ea846b36..17805aac0e85 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -268,6 +268,11 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, extern void lock_release(struct lockdep_map *lock, unsigned long ip); +/* lock_is_held_type() returns */ +#define LOCK_STATE_UNKNOWN -1 +#define LOCK_STATE_NOT_HELD 0 +#define LOCK_STATE_HELD 1 + /* * Same "read" as for lock_acquire(), except -1 means any. */ @@ -302,11 +307,13 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) #define lockdep_assert_held(l) do { \ - WARN_ON(debug_locks && lockdep_is_held(l) == 0); \ + WARN_ON(debug_locks && \ + lockdep_is_held(l) == LOCK_STATE_NOT_HELD); \ } while (0) #define lockdep_assert_not_held(l) do { \ - WARN_ON(debug_locks && lockdep_is_held(l) == 1); \ + WARN_ON(debug_locks && \ + lockdep_is_held(l) == LOCK_STATE_HELD); \ } while (0) #define lockdep_assert_held_write(l) do { \ diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 969736b33185..c0b8926a67f0 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -54,6 +54,7 @@ #include #include #include +#include #include @@ -5252,13 +5253,13 @@ int __lock_is_held(const struct lockdep_map *lock, int read) if (match_held_lock(hlock, lock)) { if (read == -1 || hlock->read == read) - return 1; + return LOCK_STATE_HELD; - return 0; + return LOCK_STATE_NOT_HELD; } } - return 0; + return LOCK_STATE_NOT_HELD; } static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) @@ -5537,14 +5538,14 @@ EXPORT_SYMBOL_GPL(lock_release); noinstr int lock_is_held_type(const struct lockdep_map *lock, int read) { unsigned long flags; - int ret = 0; + int ret = LOCK_STATE_NOT_HELD; /* * Avoid false negative lockdep_assert_held() and * lockdep_assert_not_held(). */ if (unlikely(!lockdep_enabled())) - return -1; + return LOCK_STATE_UNKNOWN; raw_local_irq_save(flags); check_flags(flags); -- cgit