From 1b963c81b14509e330e0fe3218b645ece2738dc5 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 11 Jan 2013 14:31:56 -0800 Subject: [PATCH] lockdep, rwsem: provide down_write_nest_lock() down_write_nest_lock() provides a means to annotate locking scenario where an outer lock is guaranteed to serialize the order nested locks are being acquired. This is analogoue to already existing mutex_lock_nest_lock() and spin_lock_nest_lock(). Signed-off-by: Jiri Kosina Cc: Rik van Riel Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Mel Gorman Tested-by: Sedat Dilek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/lockdep.h | 3 +++ include/linux/rwsem.h | 9 +++++++++ kernel/rwsem.c | 10 ++++++++++ 3 files changed, 22 insertions(+) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 00e46376e28..2bca44b0893 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 54bd7cd7ecb..413cc11e414 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 6850f53e02d..b3c6c3fcd84 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();