mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-09 19:46:39 +07:00
1b963c81b1
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 <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: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
142 lines
2.6 KiB
C
142 lines
2.6 KiB
C
/* kernel/rwsem.c: R/W semaphores, public implementation
|
|
*
|
|
* Written by David Howells (dhowells@redhat.com).
|
|
* Derived from asm-i386/semaphore.h
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/export.h>
|
|
#include <linux/rwsem.h>
|
|
|
|
#include <linux/atomic.h>
|
|
|
|
/*
|
|
* lock for reading
|
|
*/
|
|
void __sched down_read(struct rw_semaphore *sem)
|
|
{
|
|
might_sleep();
|
|
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
|
|
|
|
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
|
|
}
|
|
|
|
EXPORT_SYMBOL(down_read);
|
|
|
|
/*
|
|
* trylock for reading -- returns 1 if successful, 0 if contention
|
|
*/
|
|
int down_read_trylock(struct rw_semaphore *sem)
|
|
{
|
|
int ret = __down_read_trylock(sem);
|
|
|
|
if (ret == 1)
|
|
rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
|
|
return ret;
|
|
}
|
|
|
|
EXPORT_SYMBOL(down_read_trylock);
|
|
|
|
/*
|
|
* lock for writing
|
|
*/
|
|
void __sched down_write(struct rw_semaphore *sem)
|
|
{
|
|
might_sleep();
|
|
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
|
|
|
|
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
|
|
}
|
|
|
|
EXPORT_SYMBOL(down_write);
|
|
|
|
/*
|
|
* trylock for writing -- returns 1 if successful, 0 if contention
|
|
*/
|
|
int down_write_trylock(struct rw_semaphore *sem)
|
|
{
|
|
int ret = __down_write_trylock(sem);
|
|
|
|
if (ret == 1)
|
|
rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
|
|
return ret;
|
|
}
|
|
|
|
EXPORT_SYMBOL(down_write_trylock);
|
|
|
|
/*
|
|
* release a read lock
|
|
*/
|
|
void up_read(struct rw_semaphore *sem)
|
|
{
|
|
rwsem_release(&sem->dep_map, 1, _RET_IP_);
|
|
|
|
__up_read(sem);
|
|
}
|
|
|
|
EXPORT_SYMBOL(up_read);
|
|
|
|
/*
|
|
* release a write lock
|
|
*/
|
|
void up_write(struct rw_semaphore *sem)
|
|
{
|
|
rwsem_release(&sem->dep_map, 1, _RET_IP_);
|
|
|
|
__up_write(sem);
|
|
}
|
|
|
|
EXPORT_SYMBOL(up_write);
|
|
|
|
/*
|
|
* downgrade write lock to read lock
|
|
*/
|
|
void downgrade_write(struct rw_semaphore *sem)
|
|
{
|
|
/*
|
|
* lockdep: a downgraded write will live on as a write
|
|
* dependency.
|
|
*/
|
|
__downgrade_write(sem);
|
|
}
|
|
|
|
EXPORT_SYMBOL(downgrade_write);
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
|
|
void down_read_nested(struct rw_semaphore *sem, int subclass)
|
|
{
|
|
might_sleep();
|
|
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
|
|
|
|
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
|
|
}
|
|
|
|
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();
|
|
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
|
|
|
|
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
|
|
}
|
|
|
|
EXPORT_SYMBOL(down_write_nested);
|
|
|
|
#endif
|
|
|
|
|