down_write_nest_lock() provides means to annotate locking scenario where an outter lock is guaranteed to serialize the order nested locks are being acquired.
This is an analogy to already existing mutex_lock_nest_lock() and spin_lock_nest_lock(). Signed-off-by: Jiri Kosina <[email protected]> --- include/linux/lockdep.h | 3 +++ include/linux/rwsem.h | 9 +++++++++ kernel/rwsem.c | 10 ++++++++++ 3 files changed, 22 insertions(+), 0 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 00e4637..2bca44b 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -524,14 +524,17 @@ static inline void print_irqtrace_events(struct task_struct *curr) #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) +# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) # else # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) +# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) # endif # define rwsem_release(l, n, i) lock_release(l, n, i) #else # define rwsem_acquire(l, s, t, i) do { } while (0) +# define rwsem_acquire_nest(l, s, t, n, i) do { } while (0) # define rwsem_acquire_read(l, s, t, i) do { } while (0) # define rwsem_release(l, n, i) do { } while (0) #endif diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 54bd7cd..413cc11 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -125,8 +125,17 @@ extern void downgrade_write(struct rw_semaphore *sem); */ extern void down_read_nested(struct rw_semaphore *sem, int subclass); extern void down_write_nested(struct rw_semaphore *sem, int subclass); +extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock); + +# define down_write_nest_lock(sem, nest_lock) \ +do { \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ + _down_write_nest_lock(sem, &(nest_lock)->dep_map); \ +} while (0); + #else # define down_read_nested(sem, subclass) down_read(sem) +# define down_write_nest_lock(sem, nest_lock) down_read(sem) # define down_write_nested(sem, subclass) down_write(sem) #endif diff --git a/kernel/rwsem.c b/kernel/rwsem.c index 6850f53..b3c6c3f 100644 --- a/kernel/rwsem.c +++ b/kernel/rwsem.c @@ -116,6 +116,16 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) EXPORT_SYMBOL(down_read_nested); +void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) +{ + might_sleep(); + rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_); + + LOCK_CONTENDED(sem, __down_write_trylock, __down_write); +} + +EXPORT_SYMBOL(_down_write_nest_lock); + void down_write_nested(struct rw_semaphore *sem, int subclass) { might_sleep(); -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
