Commit 872fa3a2 authored by Thomas Gleixner's avatar Thomas Gleixner

rt: Fix recursive read lock of rw_semaphores

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent dcd880ed
...@@ -303,6 +303,7 @@ EXPORT_SYMBOL(rt_up_write); ...@@ -303,6 +303,7 @@ EXPORT_SYMBOL(rt_up_write);
void rt_up_read(struct rw_semaphore *rwsem) void rt_up_read(struct rw_semaphore *rwsem)
{ {
rwsem_release(&rwsem->dep_map, 1, _RET_IP_); rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
if (--rwsem->read_depth == 0)
rt_mutex_unlock(&rwsem->lock); rt_mutex_unlock(&rwsem->lock);
} }
EXPORT_SYMBOL(rt_up_read); EXPORT_SYMBOL(rt_up_read);
...@@ -314,6 +315,7 @@ EXPORT_SYMBOL(rt_up_read); ...@@ -314,6 +315,7 @@ EXPORT_SYMBOL(rt_up_read);
void rt_downgrade_write(struct rw_semaphore *rwsem) void rt_downgrade_write(struct rw_semaphore *rwsem)
{ {
BUG_ON(rt_mutex_real_owner(&rwsem->lock) != current); BUG_ON(rt_mutex_real_owner(&rwsem->lock) != current);
rwsem->read_depth = 1;
} }
EXPORT_SYMBOL(rt_downgrade_write); EXPORT_SYMBOL(rt_downgrade_write);
...@@ -343,18 +345,29 @@ EXPORT_SYMBOL(rt_down_write_nested); ...@@ -343,18 +345,29 @@ EXPORT_SYMBOL(rt_down_write_nested);
int rt_down_read_trylock(struct rw_semaphore *rwsem) int rt_down_read_trylock(struct rw_semaphore *rwsem)
{ {
int ret = rt_mutex_trylock(&rwsem->lock); struct rt_mutex *lock = &rwsem->lock;
int ret = 1;
if (ret) if (rt_mutex_real_owner(lock) != current)
ret = rt_mutex_trylock(&rwsem->lock);
if (ret) {
rwsem->read_depth++;
rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_); rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
}
return ret; return ret;
} }
EXPORT_SYMBOL(rt_down_read_trylock); EXPORT_SYMBOL(rt_down_read_trylock);
static void __rt_down_read(struct rw_semaphore *rwsem, int subclass) static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
{ {
struct rt_mutex *lock = &rwsem->lock;
rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_); rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_);
if (rt_mutex_real_owner(lock) != current)
rt_mutex_lock(&rwsem->lock); rt_mutex_lock(&rwsem->lock);
rwsem->read_depth++;
} }
void rt_down_read(struct rw_semaphore *rwsem) void rt_down_read(struct rw_semaphore *rwsem)
...@@ -380,6 +393,7 @@ void __rt_rwsem_init(struct rw_semaphore *rwsem, char *name, ...@@ -380,6 +393,7 @@ void __rt_rwsem_init(struct rw_semaphore *rwsem, char *name,
lockdep_init_map(&rwsem->dep_map, name, key, 0); lockdep_init_map(&rwsem->dep_map, name, key, 0);
#endif #endif
__rt_mutex_init(&rwsem->lock, name); __rt_mutex_init(&rwsem->lock, name);
rwsem->read_depth = 0;
} }
EXPORT_SYMBOL(__rt_rwsem_init); EXPORT_SYMBOL(__rt_rwsem_init);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment