Commit 1b963c81 authored by Jiri Kosina's avatar Jiri Kosina Committed by Linus Torvalds
Browse files

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: default avatarJiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fef6c12e
......@@ -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
......
......@@ -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
......
......@@ -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();
......
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